It wasn't so much about being "busts" as the fact that there are finite starting positions. I get the idea of 4- or 5-star guys being "busts" if they go to places where they are supposed to be the most talented and they don't pan out... like when OSU snags the random 4-star guy every once in a while... but if you're a 4- or 5-star guy at, say, Alabama, and you aren't starting because there's some other 5-star future NFL star in front of you, are you really a "bust" or is there just someone way better in front of you?
Someone like that may be better off transferring to a next-tier down program that's still good but maybe not a blood so they can play instead of being stuck behind some future NFL all-pro.
But your overall point actually sort of supports what I'm saying.
So far, it seems (with a few exceptions) the portal has largely been about QBs moving around so they can play and then just a smattering of other transfers based on who-knows-what reasons. We haven't seen wide-spread issues with blue bloods poaching players developed at other programs. The exception is probably Lincoln Riley at USC, who has had no problem doing that.