I agree with this up to a point, I agree that ANTM may not be able to afford everything that GnTM does,* but I think that they can do more and are choosing not to or do it intermittently. For example having top fashion people like Diane von Furstenberg, Matthew Rolston, Zac Posen and Patrick Demarchelier could have happened before cycle 15 because these same people have appeared on other reality TV shows, some of which were lower profile, less established than ANTM.
* but who knows because if they had splashier guests then perhaps they would have gotten higher ratings which would have generated more ad revenue which would have led to a higher budget, although in this case the guests would have had to be more of the pop culture type, which I think could have happened.