You went to a lot of effort to write a lot of things while explicitly avoiding actually answering any of my questions. This leads me to think that a simple "no" would have sufficed.
It's possible to treat people well enough that you can retain them while still not keeping promises and paying below market. There's a balance, and you can do a lot of "exploiting" before its enough of a nuisance to want to leave, and many fair things are also exploitative.
For example: refusing to hire someone because they attempted to negotiate a better offer for themselves is perfectly fair, but it also appears to be exploitative. It also becomes much easier to keep your promises when those promises are not explicit.
If no one asks for true-ups, you never need to promise them. But by not paying them, you are being exploitative. It's no different than contract-to-hire positions that exploitatively underpay people for months or years before bringing them on as full-time employees (or not doing so, for any of a variety of reasons).
EDIT: To add, since elsewhere, you explicitly mention that you undervalue new hires, the fact that you don't true-up candidates for overperformance of your (lowered) expectations is telling. Again, why would I, as a candidate, want to engage in a long term relationship with someone who doesn't put enough faith in me to pay what I'm worth, but who wants me to trust them that they'll eventually pay me what I'm worth? And who won't at least promise to make me whole during the vetting process? That to me implies two things:
1. They want me to trust them immediately, but don't want to trust me in return.
2. They won't fully compensate me for the work I'm doing.
Neither of those things make me want to trust you or form a long term relationship. If you want such a relationship, the trust goes both ways. You don't get to say "trust me that I'll eventually pay you what you're worth, but in the meantime I'll pay you less until things are verified." That's not a relationship. Its exploitation of a power imbalance.