The downside of this model is that you never get to actually build anything cool, so you either can't attract top talent, or they hate working for you and your neurotic government customer. So you have to slap on the silver handcuffs (high salary) to keep them from moving away.
It sort of poisons the well for other kinds of tech businesses. Top talent either doesn't want to be there or costs more than you might expect. Mediocre talent is happy to warm a chair to pad out a contract for the same salary you would pay to do actual work. And the dregs are the same there as everywhere else.