Would Google or Meta go bankrupt if they stopped selling ads? Yes. Apple wouldn’t.
That's pretty bad. Maybe not "reliant on ad monopoly" bad, but pretty close.
Have you considered that people just like Apple's products and services?
They sell third party ads: companies unaffiliated with Apple pay Apple to advertise on Apple platforms.
They’re an ad company. Just because it’s currently a small slice of their total revenue doesn’t make it untrue.
Making some cash on ads doesn’t have to rely on targeted tracking. That only matters if ads are an existential part of your business, and without huge ad revenue growth, your company is dead.