Yet that was historically the most successful approach in XX century for most of research-intensive industries (space, transistors, energy etc) -- when government spends crazy amounts of taxpayers money for some programs that bring little $$ back, but sprawl a lot of commercial startup follow-ups.
Investing in commercial approaches as the step 1 doesn't seem to work in multi-billion R&D endeavors.
So yes, it's not fair, but turns out to be better for the country down the road.
That works for a bit, and then all the others jostle in and start feeding on the pork. SpaceX will get this eventually too if it does well enough and settles into a routine of project bids, project management, technical project success, and more bids.
Cost-plus contracts work during wartime when everybody is motivated by the war to get the job done fast, to end the war and get their friends and family back home safely as soon as possible.
During peace time, the predominant motive is to maximize profit by dragging out the work.
Investing in commercial approaches as the step 1 doesn't seem to work in multi-billion R&D endeavors.
So yes, it's not fair, but turns out to be better for the country down the road.