Sure, there were questions about how well Harris would bounce back from his injuries, but he was the CUSA MVP last year and led his team to a conference championship. He got a six figure NIL deal to stay in San Antonio, and he finished this season as a 1st team AAC all-conference QB. He was and is a star college QB and could have made good money somewhere else, even if that amount would have been somewhat reduced due to injury history.
Rogers may very well have a higher market value this off-season than Harris did last year, but I think it still stands as an apt example of a local NIL collective deciding that it's really important to keep their QB for one more year.
I don't know if it's fair to call this a generation-specific issue. There are a lot of reasons for players to enter the portal, so without citing data, should we assume that leaving "because things don't go their way" is the dominant factor? If you were to use North Texas as an example, it seems that the vast majority of our players transferring out (according to sources with inside knowledge) were asked/encouraged to do so by the coaching staff. Sure, they could just defy the urging of their own coaches and try to work harder or something, but those same coaches hold the power to pull their scholarships, if they so choose. It would be risky/foolish not to take their suggestion. In the case of star players choosing to leave of their own volition, they are usually being offered massive NIL increases. I hate to lose those guys, but some of them have family obligations or other reasons why they can't in good conscience turn down . . .oh, let's say $150,000 to play football for a year elsewhere vs. maybe just a few thousand to stay. I highly doubt that previous generations would be any more likely to choose having their family live in poverty with that kind of money on the table. Are there exceptions to my examples, where someone bolts for little or no significant pay raise or leaves for money despite having plenty already? Sure, of course. But, I still believe those exceptions could be found in any generation. Also, one could further make the case that coaches of ALL generations are just as likely to take off for a money grab despite having committed to whatever length contract.