I'm not so sure.
Based on the figures I could find for 2021, Google's ad revenue was about $60B with approx 3B users (I asked various chat bots...).
So, if you extrapolated and did some slightly dodgy maths (there were other factors but I can't be arsed typing them) it would cost about $6-$7 per month per user if Google stopped all ads, and by extension, tracking & data mining - This is for Google to maintain their current figures.
Take these figures with a big pinch of salt though...
That $ figure is across the whole of Google. So that is for every single product they have but if you just use Gmail then it might only be $2 a month.
So, if Google wanted to make the same money without tracking, ads etc, they could but the temptation to sell your data and mine it would be strong!
Anyway, my point is that it's possible to do it but would people pay for it? I pay for my email with Fastmail so there is a single data point for you :)