B2 and F117 were built in secret. I am not sure what the big deal is.
Often times you build a prototype, and then put the mass production out to bid. Also, I am sure somewhere in the AF budget, there was money allocated to design and manufacture of experimental aircraft.
The deal is that there have been far more failures than successes when you have secret single source programs- starting with the Douglas A2D Skyshark, to name just one idiot program.
The M-16 was another single-source, no competition project and I doubt I need to remind you how it was a gigantic failure early on. (And some would say still.)