I think you don't understand Apple's brand. They would much rather charge $100 for wheels for the Mac Pro or double the cost for RAM upgrades than look cheap and have ads on basic apps.
Classiness is relative. Enshittification is real, and Apple's ad division revenue is now in the tens of billions per year. As long as their ads are typeset in a classy font and less obtrusive than those being shown by Microsoft, it won't affect their brand and Apple users will eat happily shit with a big grin on their face. Like, what are people going to do instead? Use Linux?