Not to mention that ~20 years ago, Microsoft got in trouble with the government[0], and was almost forced to break up for forcing their own software on PC manufacturers, and on top of Windows.
[0] https://en.wikipedia.org/wiki/United_States_v._Microsoft_Cor....
Google just makes sure that most Androids have the Play Store, and then it's just the network effect: bigger audience -> more attractive to developers -> more apps -> more users.
I smell monopoly. They have powers to affect most of a market. Whether Google is abusing that power (thus, illegal), I'm not sure.
For most adults/businesses in developed countries, mobile is a secondary device, while PCs run everything from AAA games to filing systems to interfaces for medical equipment.
"The Steam platform is considered to be the largest digital distribution platform for PC gaming; in November 2009, Stardock estimated it at 70% and then later, in October 2013, it was estimated by Screen Digest that 75% of games bought online were downloaded through Steam."
Puts Valve's complaints in a different perspective.
But we also don't consider iOS apps an interesting option for the software we develop because of Apple's control and fees, and we build our software with a web front end that runs anywhere instead.