> An extremely tiny minority of games are targeted for such a wide variety of platforms.
On the contrary, most games are targeted for most platforms, to increase reach and sales as result of it. Only some exclusives of console makers are not doing that, and those are clearly outliers.
> Real-time high-performance code is always tightly coupled with the hardware
That's not common at all. Unless you want to beat modern compilers with assembly code, you only will produce something worse. Sure, there are are rare cases when using hardware specific features yields extra performance. Codec developers do that for example. But for games? Not usually needed. Shaders are provided in cross platform fashion (such as SPIR-V) and that's compiled into GPU machine code by the driver. And actual game code is commonly using some high level systems language (C++, etc.) + a scripting one.
Good performance is achieved by parallelizing the engine properly, since modern hardware is increasingly multicore.
On the contrary, most games are targeted for most platforms, to increase reach and sales as result of it. Only some exclusives of console makers are not doing that, and those are clearly outliers.
> Real-time high-performance code is always tightly coupled with the hardware
That's not common at all. Unless you want to beat modern compilers with assembly code, you only will produce something worse. Sure, there are are rare cases when using hardware specific features yields extra performance. Codec developers do that for example. But for games? Not usually needed. Shaders are provided in cross platform fashion (such as SPIR-V) and that's compiled into GPU machine code by the driver. And actual game code is commonly using some high level systems language (C++, etc.) + a scripting one.
Good performance is achieved by parallelizing the engine properly, since modern hardware is increasingly multicore.