I've already explained a situation similar to Dak in this thread. Feel free to go back and read, but if you just want to freak out and be horribly pessimistic, that's your prerogative.
It's just not going to happen that much. Why didn't Matt Corral go to Alabama, Clemson, Georgia, Florida, Texas A&M? We all know he's got questionable character, so if someone was going to do it, why not him? The answer is what I've explained already, and also this little thing called team loyalty that, despite the negativity of Joe Blow Fan, many of the kids still have.
Some of this is already happening, what with all the transfers like Justin Fields being ruled immediately eligible for the blue bloods. The most egregious was the dude from Houston that went to Miami, but there again, that's a G5 moving up to a bigger stage.