OpenGL for FMX

[Akira13]

It's because FireMonkey is based directly on the codebase of DXScene by Eugene Kryukov. DXScene was itself just a proprietary fork of GLScene that used Direct3D 9 as a rendering backend instead of OpenGL. (And to be quite honest it was always just a lot worse than GLScene in every way, since like 80 to 90 percent of the useful aspects of the library were stripped out for the purposes of "simplification".)

So yeah, to make a long story short: FireMonkey is a fork of a bad fork. The only reason Embarcadero went back to using OpenGL on other platforms is because DirectX doesn't exist on those platforms. If you want something that works similarly to FMX but is way better, just use GLScene itself, which has always remained actively developed.