Re: It's about pork
You're right in that reusability isn't SpaceX's only way of saving cost - adding reinforcement by use of friction stir welding (instead of taking a thicker structure and milling away material) is another example.
However, I'm not sure you've made the case for NASA's procurement process being safer for crews clearly enough. The Challenger disaster was famously due to there being too many managers sitting in between engineers in different organisations. When SpaceX has lost craft and payloads they've been able to chase down faults fairly rapidly due to their all in-house nature.
SpaceX is no longer seeking to have the Falcon Heavy certified for manned missions, instead stating they're concentrating on doing so for the BFR once they've made it. The problem is that the market for BFR-scale payloads is smaller than for Falcon-scale payloads (modern electronics allow for smaller satellites). This means that it will take a longer time for the BFR rocket to accumulate the same number of successful unmanned launches as the Falcon has (approaching 50). One assumes that a large number of successful unmanned launches can only aid certification for crewed launches.