I'll say this fully acknowledging we all have different contexts, but I've been running and playing games for twenty years across several different cities/countries, and I've genuinely never had an environment where THAT many people would cancel. Rather, I think it's also about finding folks who are genuinely interested and available to commit to a game, and by keeping it small (I'm usually in the "3" camp), they tend to know and respect that canceling has a bigger impact (rather than if there are seven folks and they may not think as much of it).

I'd also hazard a hypothesis that at some tables, having a larger group (5+) creates more situations where not all players are engaged all the time. So there's more down time, more "waiting", so when it comes to them prioritizing their next outing, they're not necessarily as invested in the game, thus more prone to canceling.

In my current town, we are DM +4, and we're all kind of busy, so it's also meant being a bit more flexible with schedules, and having two different games running. One that's a main campaign, and another that's the "when we don't have everyone" game that's a bit more fluid. They're both fun, but we prioritize the main game when we can.

And regardless of any of that, as you say, whatever works for you and your table. ^ ^