I wonder if the OP has actually ridden both newer and older bikes.
I have both a road bike from the... well, late 60's. With several updates over the years.
And, I built up my first carbon fiber bike a couple of years ago (with a frame from the late 90's, and newer components).
Wow, riding the CF bike, it just felt like a bike should feel (I suppose I should try an even newer one).
My old toe clips.. I was happy enough with them. But, much happier when I changed over to SPD pedals.
I never liked braking from the hoods with the old Universal brakes. But, it is just so natural with the new brake levers.
I ride from the bar tops... and the flattened "aero" bar tops are much more comfortable than the round ones.
I haven't gone to disc yet, but the new(ish) Ultegra 6800 dual pivot brake calipers are very good.
Man, I got a lot of flats with the Sewups.
New tires are just better.
I just never was satisfied with the 13T or 14T high end on the old freewheels. I suppose it is a bit of my riding style, but the newer cassettes work nice.
I have some touring upgrades planed. The old bike is just so flexy in the rear end. Hopefully I can eventually solve that issue.
I still like the old bike... but some new stuff is well... just better. Not everything. I think many of the cassettes wear faster than the freewheels. But, a lot is very good.