How many people even experience ads in gmail? They aren't there on Workspace or EDU. They aren't there on gmail.com unless you are using the tabbed inbox with the Promotions tab enabled, and you visit that tab. Which, honestly, who would?
I'll be honest, I was under the impression they stopped showing ads on Gmail when I was writing this. I actually google'd it but couldn't find any news source citing that google stripped ads off gmail so I omitted to mention it.