That is a really interesting question. Why do all higher end bikes seem to have carbon components on them even if their frame material is different.

I don't think that statement is arguing the point, but rather supporting the premise. If any other material is so great, why do they have carbon components on them instead of that material?

Coming along quite nicely, although I consider the builder sending me this one big tease:

Like was said, Ti or Al are excellent for the frame, CF is excellent for the fork. Why should you expect both parts to be best served by the same material?

I think economics is the answer- Ti is tough to machine, & getting a performance fork shape out of it would be not worth the expense-
you don't see 'fully manipulated' tube shapes in those closed triangles either.

I think if we saw CF frames with Ti or Al forks, it would be similar. But what we seem to see is either all carbon or X material + carbon. It sort of paints the picture that all CF is most builder's idea of the best material to use.

Actually you do. At least on both of the Ti frames I have had. Not hydroformed, but highly shaped. Recent Ti tubes are pretty complex.

Apparently there is no reason for that. The point is that Ti is thought by many to be good for the frame. Fewer people think it is good for the fork. Fair enough. That doesn't make their assessment for the frame incorrect.

I.E. in Indyfabz's frame picture above, the tubes each appear to be uniform diameter- nothing tapered.

Ti can be plenty stiff, carbon can be extremely comfortable. So, setting that aside Ti's appeal to me is mostly practical:

1. There's no paint to scratch on most Ti frames.
2. Cable rub or other small scuffs can be fixed in five seconds with Scotchbrite if your bike is finished like mine. Available at Target.
3. Apply a little Pledge (also available at Target) and you have a shockingly new looking bike, even if it's 20 years old.
4. I can toss it in the back of my car without treating it like it's made out of eggshells.
5. Metal frames like Ti almost always use standard round seatposts and standard clamps. This design is the best to work with: easy to buy parts, easy to get the saddle dead-on straight and no risk of slippage.
6. You don't need to worry about cracking the frame by overtightening a seat post clamp or bottle cage. Ti is extremely tolerant.
7. Cool "pinging" metal sounds while shifting or from cable snap.
8. Ultimate crash resistance.
9. Try to find a carbon frame with a threaded BB that's not a mega-buck Italian brand.
10. Go ahead: clamp the top tube or seat tube on the workstand if you must. You're not going to crush anything.

Steel's even tougher than Ti but it rusts without paint. Stainless is even more expensive. Still, I crave a 953 bike.

Because it's lighter than steel; but more cushy than Ti. for a sensitive thing like a fork, which accounts for a good deal of how a bike rides and how much vibration and nastiness from the road it transmits. The bike-shop dude knows this...he just assumed that you don't.

The bike shop dude was trying to sell me a domane.

Precisely!

I could just picture him... "Pfffftt! If Ti's so great, why're the forks on all of 'em made of carbon fiber?"

If he had been trying to sell you a Lynskey, he would have been like "Ya know, these things won't break if a feather lands on 'em, unlike that CF crap!".....

See my Everti Falcon a couple of pages back. I think you can see the tube shaping especially if you blow it up a little. And that is not an expensive frame.

I had to go with Titanium because it was cheaper than steel.

I've had my Colnago Super (steel bike) for 33 years now, and it is approaching its 50[SUP]th[/SUP] birthday. And the paint is just really bad. I think it has either serious UV damage, or simply dried out. Anyway, multiple wear spots, and where the paint isn't worn, it is just flaking off. And rust is showing through everywhere. Not a pretty sight.

So, now with my "new" Litespeed. The decals may eventually wear off. But, it will never need repainted. It makes a serious rain bike that I can just wipe down.

As far as forks.
Colnago used steel forks on many of their Titanium bikes.
A few Titanium forks are available, but expensive, and the Chinese ones just don't look quite right.
I currently have a bonded aluminum fork on my Litespeed, and it is doing well for me. I did track down a CF Litespeed fork, but I haven't decided whether I'll mount it yet. I'll probably ride the aluminum for at least for a while longer.
Keep in mind that many aluminum frames also use carbon fiber forks, and sometimes seat stays.

Anyway, I'm riding Titanium at the moment because it was cheap. And, so far, it seems to be quite durable. However, had I not gotten the deal on the frame that I got, I'm not convinced that I would have been better paying more for a titanium frame than I would have otherwise paid for 3 or 4 steel frames. Say I got 10 years out of each steel frame... then upgraded... I could always have one looking nice.

On that theme, it helps explain the existence of other bikes with a bit more CF in the tubes coming from the wheels, but with Ti tubing elsewhere.

And you haven't even considered replacement decals and/or repainting. Your old steel could be reborn. Your Ti can stay fresh with new decals until long after you cease to care.

Fashion. Your choices these days are mostly that or black anodizing which imitates carbon fiber like laminate flooring pretends to be wood, and unlike the real thing scratches are a different color from the surface.

Some parts need to be a certain size without much strength. Plastic (Carbon Reinforced Plastic, aka "Carbon Fiber" in the vernacular) is lightest followed by aluminum, titanium, and steel. That matters on paper and people care, although the practical impact may be insignificant - my carbon fiber brake blades save 21g over aluminum although that's only 0.02% faster up-hill saving one second on an hour long hill climb.

Manufacturing constraints. You can make aerodynamic wheel shapes you can't extrude and bend into a rim.

Manufacturing costs. A molded carbon crank is less expensive to make than a forged hollow aluminum crank.

Marketing that's convinced people to pay more for carbon fiber.

I'm not opposed to that look with carbon fiber cranks, brake levers, rear derailleur parts, and in my hub shells; although being honest that's what it comes down to.

Enjoying a nice, tall glass of Haterade?

Yep, the old Colnago will likely get a new coat of paint... or even powder, although there are threads on whether one should keep the wear as "patina" so I'm still considering. However, winter cycling is hard on it, so I wanted to get it off the road in the winter, and needed to ride something while I do a restoration (of sorts).

Absolutely! While I only have time for 2.5 hours of riding on week days, the rest of the day there's always a computer nearby for amusement.

I've been known to enjoy a glass myself

that is a sweet Titanio!!! Yours?? That is probably tops on my list for the N+1!