On the planet I live on, based on actual riding rather than reading articles, there's no way a wider, softer tire is as fast or sporty to ride as a 700c road tire. I don't care what "they" say. Look, I'm no speedster, but I like to ride as fast as I can within my limitations, I like fast acceleration, and I like speedy, agile handling around sharp bends and descents. I also like to feel the road surface. For me, that's what riding a road bike is all about. But if ever 700c is abandoned in favour of 650B, I'm Ok. My sport touring frame can easily handle them. I would only need to swap the brakes for longer reach ones. But I have no desire to do that whatsoever at present. I love today's superb road clinchers. They are almost like tubulars but without the hassles.

I think that contrary to what you read about on the internet, for most French people, 650B evokes thoughts of old farmers riding out to herd the sheep or goats on old 650B clunkers rather than cyclotouriste constructeur bikes. I think the latter is much more an American-based idealized stereotype about French cycling.

By the way, contrary to popular misconception, a 650B based frame is no more suitable for a short person than a 700c based one is. A 650B wheel with a typically wider 650B tire on it is roughly the same dimension as a 700c wheel and tire. We're not talking 650c here.