Except it can't really be ramped up. It's enormously expensive to build a single F-35, let alone maintain them, and the geographic distribution of the effort only makes that worse.

And then they made it worse again by making many parts of the F-35 F-35 specific. You can't just drop in the same radio LRU from most other airframes and use it with the F-35, it has its own and its own maintenance cycles. The thing was designed to be expensive, it was not designed for manufacturing efficiency.