I left DCC and only had limited experience. I run MTH's DCS exclusively with their decoders in almost everything I have. A few stray G scale DC engines are waiting for upgrades and I have a few TMCC equipped O scale engines laying around.
That said, I really feel that some companies target HO scale for easier amp loads and larger sales. I don't think there's equal demand for O scale decoders to make every manufacturer consider releasing a higher amp decoder. I thought the standard was to use a NCE version for motors and a separate sound decoder? I believe G scale may have even less overall demand?
I believe that Lionel and MTH have the O scale market pretty saturated??
When a certain manufacturer attempted their higher amp capability, there was some postings about high heat being generated. Some users won't try other brands than the one they stick to anyways. Seems that they focus on low price over features and the other "bells and whistles".