Of course - as incomes rise, some people use that extra to travel. And flights are cheap and frequent (compared to years ago).
This is why I like to do a combo of big and small. We spent 5 nights in Amsterdam last year, but then spent 3 nights based in Dordrecht. Our first trip to Italy, yeah, we hit Rome and Venice, but also stayed a night in Genoa and Bologna (not that they are 'small' - but they are generally less touristy). When we went to Germany, we stayed in Augsburg and Munich. In Switzerland, we stayed in Zurich and Bern, but also Spiez.
And tho I do like to be close to the action in big cities (I want to get out early and don't want to spend too much time on a tram or metro or my feet) - I'll still try and stay a little out of the tourist centre. In Amsterdam, we stayed in the De Pijp area - which, while not right on a canal, had more of a residential feel, yet had tons of restaurants nearby and was only a 5 min tram ride to Museum Sq. Had we stayed right in the centre proper, if most likely would have felt more crowded/stressful.
And for me, I do find the nice thing about returning to a big city multiple times - we've already seen the big crowded sights over a couple of visits, so it's easier to go to the smaller museum, or the off the beaten path church or that neat little neighbourhood. I mean, after travelling to London 6 times, we don't need to see Westminster or Buckingham Palace, or ride the London Eye or go to the Tower of London. Let's go to the Grant Museum or the Museum of Brands (!?). But trying to get on the Tube in the mornings or afternoons is still soul sucking. :)
So what works for me is staying in a smaller place in between the big cities just to lessen the annoyance of crowds.