Anyone else who proposes to develop at the scale that Amazon was proposing, would likely be achieving similar tax incentives as to what Amazon was offered. Particularly since the terms of the deal were made public, that becomes an anchor point for any similar discussions.
There is no question that organic growth will eventually create 25,000-40,000 jobs. But the net present value (NPV) of that future job creation is significantly reduced after applying the discount. So even the same number of jobs is not a comparable economic impact.