The X1 Carbon series is popular with Linux kernel devs, so it’s had a lot of TLC. It makes a big difference for some stuff like sleeping. My Thinkpads handled sleeping really well, and I could expect to leave it sitting for at least a week and come back to somewhat low battery. My Framework laptops, as nice as they are otherwise, will drain the battery during sleep in 24h, no matter what I’ve tried. The situation is apparently better on the newer-gen Framework laptops, and IMO Framework’s open nature will lead to a similar situation to Thinkpads, but it’s not quite there yet.
Apart from sleep, I’ve heard complaints about the manufacturing quality of some of the other options, but haven’t used them myself so can’t verify. Might be why some people recommend the Thinkpads, though. I do really like the quality of the Framework, and I’d recommend people take a look at them over Thinkpads now, unless they care about sleep battery usage.
To chime in with some of the other answers, price also makes a difference. Thinkpads have been around long enough that there’s a nice large used market. I got a rock-solid Thinkpad T480 for a few hundred dollars from some dude on Craigslist. My Framework is higher-specced and was paid for by my work, but it still starts out ~$800. I think it’ll just take time before other manufacturers have a similar situation.