I've had my Model S 85 since '13. It is still like new, in great condition. Yes, it doesn't have AP, etc... but I've never kept a car this long. I've always wanted something new. Not this time. I'm just waiting for a refresh of the Model S and will buy again. We bought two Ss in 2013 and have since added two Model 3s to the family, one P3+. True, service, imo, has lacked as more cars have been sold. That's my biggest gripe. Early on is was very personal care and always a Tesla loaner. It was a gamble getting one early on, but we've never regretted it.
As far as losing its value, all my cars have lost a lot. I feel anyone buying a 2012/13 Model S is getting a bargain!