Contract subsidies are kind of coming back in the form of "trade in bill credits.". Previously you'd sign a 2 year contract and they would subsidize your phone, however; I just got $800 of trade in credit at Verizon for a phone they normally give $150 for.
The catch, of course there are many... the bill credits are over 3 years, and in my case fully offset the cost of the monthly phone purchase price; if you leave you need to pay off the remaining balance, and if you upgrade you lose your credits. Also you need to be on an unlimited plus plan.
However; I now have a new phone with no additional monthly payments. The last Samsung I had made it 5 years, and the new one actually has a serviceable battery!
If you break your new phone, you can't fall back to your old one and you will have to pay over MSRP for a replacement if you buy it from your carrier. That's the real reason they want you to trade the old phone. That and to kill the resale market.
I ended up getting the S23 Ultra, (had to come out of pocket a bit), and if you get Samsung's Care+ insurance it's $8 a month, so basically $100 a year if something goes catastrophically wrong. I will probably carry that insurance for the first two years or so of owning the phone. Given I rely upon my phone for a ton of business, my home phone, social communication etc, it seems fairly reasonable as they claim to have 24 hour replacement.
Technically, but not like it uses to be... the back still has to come off which uses adhesive, and a few little cables have to be moved, but you can check out a few tear downs. I don't understand why we can't have water tight backs that use an O and screws, but I guess that would make it to easy to fix things, so lets use more glue.