Resolutions were very high for the time, I have a 2002 LG f900p (pretty high end, yes but it wasn't super expensive even back in the day) running at 1920*1200@85hz and it's a delight to work and play on it.

IMO, the only factor that kills the crt vs a moderm monitor is the size and weight. I imagine resolution would be limited by how small the dot pitch can actually be made to be with modern processes but with the advances in magnets and power electronics devices I imagine going at MHz horizontal frequency would be not that hard.