The bayer filter not only removes precious spatial info but also filters out a lot of photons. Foveon was an interesting direction that sadly proved to be impractical, but there is hope. Dual gain exposure would be nice, and starts to appear on some cameras I think. I would take 24MP with full RGB info per pixel over any 45-60mp bayer image any time. That said, when time is not an issue, 45mp pixel shifted images are awesome.
In the meantime most of the progress will come from computational trickery, like high speed multiframe stacking and other AI hacks, exactly what phones do.