So, when employees want a raise from their employer, they generally have to work at the higher level for a while before they get the raise. Essentially working at a discount for a while, until the employer has decided to give the raise.

Why don't we require the same of companies asking for tax breaks? We'll give you the tax break AFTER you've been around for a bit, and you've proven that you're worth it, and that you'll actually do the things you promised you'd do.