I bought the hardware, for the price they chose to sell it at. Why should I be obligated to use any of their services, if I can avoid it?

I'm not sure if your comment is satire. So I'll respond as is.

"Not providing potential further income" is not "robbing"... what is being stolen from them? Something they never had in the first place? When I lose a bet I willingly entered, am I being "robbed" of the gains?

Furthermore, who is losing if I go to F-Droid to install an open source app people wrote with no expectation of income? If Google had a better app, I would have installed it from there. Too bad everything is riddled with ads detracting from the core purpose.