Comment by bryanlarsen

SpaceX is very close to demonstrating an architecture that ameliorates almost all of the drawbacks of two stage to orbit architectures. The tyranny of the rocket equation ensures that while a SSTO carrying all of it's oxygen is possible, it's never going to be able to carry enough mass to be useful.

Therefore nobody is ever going to invest the tens of billions required to develop a rocket based SSTO.

If somebody develops an engine that makes air breathing most of the way to orbit feasible, this has a chance of competing a Starship style architecture.

For the reasons you espoused, this is highly unlikely. However "highly unlikely" is more likely than "never".