I pay for Fastmail and I get a relatively large amount of spam there. We self-host our email at work, and plenty of spam gets through there, too. I never see spam in the inbox on my gmail address, ever. Google's email is the best I've seen (though I admit I haven't used a lot). I use it because I want to use it, not because it is free.

I'm not sure what you mean by "buy email from google today." I don't want to "buy email," I want to pay them to not serve ads or track me when I use their services. That includes far more than email, I'm talking about the whole ecosystem like Android, Maps, Search and so on. Surely $120/year from me is worth far more than they're getting in ads, right? I dunno.