[azernik]

Falcon Heavy is a vehicle that uses a heavily modified Falcon 9 first stage in the middle, and has two more-or-less standard Falcon 9 first stages as strap-on boosters. (These first stages are sometimes called "cores".)

The side cores for this flight are reused Falcon 9 first stages, while the center core is new. Falcon Heavy center cores are structurally reinforced, and hence are different enough from Falcon 9 that you can't reuse one as the other; whereas converting between Falcon 9 first stage and Falcon Heavy side booster just involves moving around some external hardware.

The government has done good work on this issue - it's bootstrapped a market for launches using its purchasing power in military launches and ISS resupply contracts, while actively working to preserve a competitive environment and avoid monopolies. It also provides essential services like range safety and airspace management; what's getting in SpaceX's way is the lack of government.