They were young -- probably late teens. Unlike some bike shop employees, though, they were really into bikes. They weren't just working there to earn some money. One of them owned at least one Dura Ace equipped mid-80s Italian bike, and they had both ridden many different contemporary models.

I did not feel that they were out to sell me, though I can see how that might happen in other cases, and probably (make that certainly) does happen in other cases.

They seemed to believe what they were saying.

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[side note: It may be true that there were and are all kinds of bikes made then and now, and in-between (and before and after, for that matter); but it does not therefore follow that there are no population differences. Probabilities can sometimes be useful. The differences may not apply in all cases; but they do apply in many.]

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Back to the bike shop guys. So I suppose what might have been happening, in part at least, was that they have been brainwashed (by Shimano and others) into thinking that bikes have evolved tremendously in the last twenty years. "Twenty years of technology" one of them said -- and he meant it -- as if talking about computers -- as if there was no comparison between then and now. To them it seemed out of the question that these older bikes could even come close.

[It all started by the way, when I was asking one of them about an older bike I was considering. After some discussion, he was the one who came out and said that even a six hundred dollar bike of today would handle better (than any of the bikes made then). I was skeptical.]

I said Okay, they are lighter, and the drivetrains have improved quite a bit -- but what if you are just going down a long hill in the mountains, on a windy road, or just on a recreational ride, and the shifting is not an issue -- is the handling really that different?

They said it is.

"The geometry is completely different."

Both of them said this, and repeated it.

It didn't seem true to me at first -- wheelbases are similar in many cases [aren't they? -- and isn't this kind of thing published somewhere?, can't it be checked or verified, independently of opinions, however strong they may be, or however strongly asserted?], head tube angles, seat tube angles, rake, trail....

One of them just shook his head -- he seemed genuinely convinced.

The other repeated it.

Somehow I was outvoted....

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When I asked the second one if he agreed with the first guy, that today's bikes handle better, he said that he actually disagreed with that.

He said, "They handle MUCH better."

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I was a little taken aback.

He mentioned driving a Honda from the '70s vs one from 2007-2008.

That 'makes sense' in a certain way; but in another it does not. It is a selective analogy. It may be misleading rather than clarifying. One could find some other analogy that would put things in a very different light.