I think most of these $20/mo subscrptions will either be Apple's iCloud, Microsoft's Office 365 or Google's Drive+Office plans which already do or will offer bundled AI.
I know Google gives me free Gemini AI from my Google Drive plan. Microsoft probably already does too, didn't test. Apple is probably crafting some arrangements if not offering already.
My point is most people wont pay for AI. It will be bundled.
And I think AI is going to be free for all, with ads.