It’s just a different layer of abstraction. The chips on your SSD in your thinkpad are also soldered without any easy way to replace them save for replacing the whole SSD. Same for your RAM. Now in a modern laptop it’s the top case or bottom case or board; the robot-made factory parts are bigger integrated components of the system. All you care about is your data anyway, the repairability of the system as a whole by…
Maybe you have the main motherboard with CPU, RAM, and possibly GPU all together. Save space - integrate bigger and better batteries.
Swappable storage though seems like a no brainer (especially because even the fastest SSDs don't require the kind of latency and link speed soldered RAM might). A modern card type slot for peripherals seems like a damn nice addition too along with the ability to swap the WiFi chip.
Hell I would even settle for an easily swapped mobo with soldered parts if I wanted to upgrade down the line - a good screen and keyboard and chassis can last a long time !