I'm in my mid 30s so maybe a different perspective than the OP, but I don't really consider ever "retiring" in the traditional sense of the word. I think the work place is changing drastically and will continue to do so going forward. I see myself perhaps shifting my role as I get older, but not really needing to fully retire. Maybe I go to 30 hrs a week so I can keep my benefits. Or maybe I go live wherever I want and work remotely. I won't ever stop working until I die, I might just shift what a given day looks like.
Of course, I work in a field (Civil Engineering) that is starving for talent. Even now, once you get to the senior level, assuming you're a valued employee at a good company, they will do most anything to keep you. You can get a well paying job that is fairly relaxed without too much effort. More and more, the corporate life is changing to "work where you want, when you want, just get your job done."
Back to the OP, I'd be hesitant to make such a change so close to the finish line. As others have said, the grass isn't always greener and you might find that the extra $13,000 a year was not worth the pain of the change. Think of all the political capital you've built up over the past several years, that immediately goes away when you change companies (schools).