Only if they have forgotten the DC-X, which I doubt they have done.
I guess they didn't ask the people who designed and built the Apollo lunar landing modules in the 1960s?
The lunar module was navigated and landed by a human pilot (with computer assistance).
The descent stage stayed on the Moon, and wasn't reused (except as a launch platform for the ascent stage). The ascent stage also wasn't reused - after the astronauts exited from the ascent stage into the command module, the ascent stage was jettisoned to crash into the lunar surface (or sent into solar orbit). Only the command module returned to Earth.
It never becomes mathematically impossible to achieve escape, but it can become engineering-impossible, ie the propellant fraction becomes so high that it’s impossible to build a structure that can contain the propellant and maintain mechanical stability. Just for reference, modern rockets are 90+ percent propellant by mass.
For more, see https://www.nasa.gov/mission_pages/station/expeditions/exped...
Tesla seems to be having some severe growing pains, but I have learned not to count Elon or any of his ventures out. Self-landing reusable rockets were impossible too according to pretty much the entire aerospace industry. If it comes down to it Tesla could still raise quite a bit of money almost overnight, albeit probably with more dilution than they would prefer. I have little doubt that they will eventually scale up. Question is how much blood they will have to spill in the form of liquidity and market cap before they get there.