Post-USSR, the DoD literally met with defense companies and told them that (a) there was going to be less money so (b) they needed to consolidate to survive.
It was pretty explicit.
That said, I don't think it's necessarily a bad thing.
Everyone forgets that system complexity increases generation by generation: an F-35 is not an F-111 is not an F-86 is not a P-51.
The unconsolidated, smaller defense companies of yore likely couldn't have managed a project of F-35 A+B+C complexity.
