It has also come to a point where none of the extensions makes sense for me. 512GB is plenty. RAM might be an issue - but I honestly don't have enough data on that. The last time I had more than 16GB RAM was in 2008 on my hand built desktop.
As long as the battery can be replaced/fixed - even if it's not user serviceable, I'm okay with that. I'd guess I'm not in the minority here. Most people buy a computer and then take it to the store even if there's a minor issue. And Apple actually shines here. I have gotten my other laptop serviced - but only in unauthorized locations with questionable spare parts. With Apple, every non-tech savvy person I know has been able to take to an Apple store at some point and thereby extend the life.
That's why I believe having easily accessible service locations does more to device longevity than being user-serviceable.
(In comparison, HTC wanted 4 weeks to fix my phone plus 1wk either way in shipping time and me paying shipping costs in addition to the cost of repair. Of course, I abandoned the phone entirely than paying to fix it.)
We could actually test this hypothesis - if we could ask an electronics recycler on the average age of the devices they get by brand, we should get a clear idea on what brands actually last longer.