Yup. I have two working t420s (t420s is thinner than t420 and I think puts it in the realm of "acceptable" in modern standards. T420 I find is mostly a stationary laptop). They run upgraded ssd drives and ram.
I also recently stocked up on 3 used t480 as it's the last generation with easily removable battery as well as drive and memory. Those should last me a while! My primary daily driver is the 6 year old t25 - basically t470 but with good keyboard.
But I think... That's kinda the point. These laptops were upgradeable but modern ones are not. T490 and onward don't have external replaceable battery. A lot of modern thinkpads have soldered ram. And none of them have the elegance of ultrabay of yore.
The T480 and older have two batteries; one fixed internal and one removable external. It transparently switches between them, so you can hot-swap the external with out any interruption. Fantastic feature!
Right but that's a) compared to 5 seconds with external battery and b) requires certain comfort and skill level and c) as you point only for specific laptops
Regarding c), I personally never get anything but business laptops. The consumer ones are just too crappy, plastic everywhere, won’t last more than 3–4 years, underspecced hinges, and plastic clips.
The business ones are the same price or cheaper past the three years mark when IT departments all get rid of them at the same time and spare parts are plentiful for the next decade.
I also recently stocked up on 3 used t480 as it's the last generation with easily removable battery as well as drive and memory. Those should last me a while! My primary daily driver is the 6 year old t25 - basically t470 but with good keyboard.
But I think... That's kinda the point. These laptops were upgradeable but modern ones are not. T490 and onward don't have external replaceable battery. A lot of modern thinkpads have soldered ram. And none of them have the elegance of ultrabay of yore.