And adding onto this it's not just cost, they also have the fastest turn around and the highest reliability.

It's vaguely analogous to the early automobile market where Ford was dominating by every single objective metric so competitors were left to compete on subjective metrics like styles. Incidentally this era is where planned obsolescence really took off.

Unfortunately for competitors I'm not sure coating a rocket in a chrome finish and running a sleek ad campaign is going to beat out price+speed+reliability.