This place was always packed, looked like a local spot.
Chamonix has a resident population of about 8500 of which around 1000 are foreign nationals, the coffee shop you visited is owned by 2 Brits. Last winter Chamonix recorded 3.26 million overnight stays, so the place is usually crawling with tourists. Nearly all the businesses there cater mainly for tourists, just over 50% of which are French, of the rest 25% are Swiss, 20% British and 4% are from the US.
You don’t need to be a good skier to ski the classic route down the Vallee Blanche, as long a you can stop reasonably quickly you should be good to go. The tricky bit is the arête, these days most skiers use crampons, but lots of them don’t know how to use them, be wary of people going down backwards, if they slip you could be impaled on their crampons.
The Mer de Glace has lost a lot of ice since 1985, until a few weeks ago there was a 100m climb with 550 metal steps from the glacier up to Montenvers, now there is a 10-seater gondola lift.
If you do decide to go back to Chamonix make sure you avoid French school holidays and check out the conditions, as these days they are often far from ideal. I used to ski there a lot during the 1980s / early 90s, Chamonix is about 1½ hrs from where I live, but I hardly ever go there now.
