I note there have been a lot of moving parts over the years.
I grew up in Michigan and went to college in that same era–not Michigan but a bunch of HS friends did. The running joke back then was there were more kids from NJ than Michigan at Michigan. Obviously not literally, but there was in fact an observable pattern of advantaged kids from states like NJ choosing publics like Michigan instead of their in-state flagship.
The thing is, the year I graduated HS, OOS tuition at Michigan was $5964. Even accounting for inflation, that would be like $15,600 today. And now OOS tuition is right around twice as much.
In terms of the difference, it looks like Rutgers in-state in that year was $3765, so $2199 difference in those dollars, about $5740 today. The difference is now closer to triple that.
Of course Michigan is not hurting for kids willing to pay so much OOS–that is why it charges so much.
Still, I do think SOME NJ families that would have considered Michigan over Rutgers at the old difference will reject the new difference.
And not just Rutgers. I think in general, many “flagships” and similar are getting more of their state’s top students because the pricing of nominally “better” OOS or private options has gotten less and less competitive over the years.
Which then might feed into better reputations, and it becomes an effect that builds on itself. Not quickly, but I think observably over time.