Comment by ThePhysicist

Just wait 5-10 years and it will probably be the same way on Windows and MacOS. They will argue that installing arbitrary, unvetted software through the web is dangerous, so it's only reasonable for Microsoft and Apple to make this very difficult and instead promote installing all software through their app stores (which they already start doing). Once software is primarily distributed via these stores they will also start asking for a cut of any revenue that is made through that software. The reason it's not like that already isn't that they're very nice, it's just that historically computers were open platforms and it will take longer to convert them to the walled gardens that smartphones have been from the very beginning of their existence.