Google is really leaving the door open here for Apple to step in and offer a services bundle with a monthly fee that doesn’t involve stuffing advertising into every nook and cranny of the user experience. I generally prefer Google’s services to Apple’s but there might be a tipping point soon where I’m willing to sacrifice some features in exchange for a generally less creepy product.
You are assuming people would pay for an ad free GMAPS. Google tried this with YouTube Red. It doesn't work. Apple users may be willing to pay for apps, Android users don't swing that way.
YouTube Red isn't a good example. It seems to work just fine. Google is famous for being willing to cut loose efforts that don't work, and they haven't stopped YouTube Red -- they only rebranded it.