Here's the 2016 results where older voters (65+) preferred Trump to Clinton. I also grew up in one of the biggest retirement communities in Florida and while anecdotal, many of them would tell me they were Democrats when they were younger and shifted right as they got older.

I would say, that as you get wealthier, you tend to want to protect that wealth. And older folks are wealthier than younger folks. That's my biggest guess.