Russ is spot-on, we have hit a technical wall, progress from here will be materials driven first, if at all.
Filament printing currently has capability limits that might not be financially feasible to overcome.
All the fancy X,Y,Z drive designs in the world cannot solve the problems of forcing a very viscous fluid through a very small hole with complete control.
Coming up with new materials with fast transition from solid to liquid and back again with greatly decreased viscosity while maintaining stability and strength is a huge ask.

It is easier to turn to an SLA printer for improved resolution than it is to devise a way to make filament printers match that standard.