See, you're confused because you think that the media player is owned by Netflix.
The browser gives you a certain level of control on computers, although you have to deal with the oddities of Safari, but when you go to smart TVs it's the wild west. Netflix does provide their tested framework to TV vendors but it's still not easy, because media playback often requires hardware acceleration, but the rendering framework isn't standard.
Developing for set-top boxes, multiple generations of phones, and smart TVs comes with all sorts of oddities. You think it's easy because you haven't done it.
The browser gives you a certain level of control on computers, although you have to deal with the oddities of Safari, but when you go to smart TVs it's the wild west. Netflix does provide their tested framework to TV vendors but it's still not easy, because media playback often requires hardware acceleration, but the rendering framework isn't standard.
Developing for set-top boxes, multiple generations of phones, and smart TVs comes with all sorts of oddities. You think it's easy because you haven't done it.