Writing this on a first-gen 13 DIY, so it's already a bit dated. I've already added additional RAM and swapped in a much bigger SSD (really underestimated how much space you need if you heavily use docker and VMs).
The 1st year was a bit bumpy with 4k monitors over a USB-C hub being somewhat flaky. Ever since a clean Ubuntu reinstall, I'm very happy, no complaints whatsoever.
Sure, it costs more, but the combo of perfectly running Linux, giving me the piece of mind of repairability and easy upgrades for me justifies a higher price.
On the other hand, I'm not willing to pay the kind of premium you have with Apple products, where for incremental steps in more RAM or SSD you pay a multiple of the off-the-shelf price of the added space.
You do realise you can upgrade RAM and SSDs, as well as replace most components on ThinkPads too, right ?
"Most components" seems a bit of an understatement when compared with the Framework.
Sure, some components can be replaced. And not at the same cost (opening and manipulating the Framework vs the ThinkPad). But not all, like the motherboard.
I may have built multiple dozens of computers in my life, so it's not that I'm new to this world.
Replacing the motherboard is just not an important thing, and that's demonstrated by how Framework has remained a very niche product.