O'Brien actually restored PSU Football Inc. by struggling at first and then pulling off some upsets (Wisky). Winning begets recruiting which is why it was easier for Franklin to shine on the recruiting trail despite his horrid hires at DC and OC.
I'm not an O'Brien fan. He stayed with the Patriots while our roster was falling apart. He explained that by saying PSU didn't hire a coach for 2012, the hired a coach for the next 5 years. He told recruits that he intended to honor that but he jumped at the first NFL opportunity. IIRC D Barnes said everybody has to look out for themselves which I don't think was a great message for the players.
I also don't think O'Brien restored PSU football. He inherited a very strong roster absent Fortt, Fera, Brown, & Redd. They had clearly superior talent than Ohio & Virginia but they were completely unprepared.
I strongly appreciate the kids who stayed but I think the thing that saved PSU was the incredible fan base that had been built in the previous decades.
Franklin inherited a horrible situation but was able to get things turned around in 3 years. I attribute that to striking gold with McSorley & the fact that he already had strong recruiting connections in the northeast. That's something Campbell is going to have to build from scratch.