The reason is simply that there are not enough incentives for manufacturers to do so. I would be happy if nothing on smartphones was glued together but everything was screwed or plugged in, and if I could simply replace batteries in smartphones and laptops, as was the case in the past. If these things are not made mandatory requirements, the thinner device, the lighter device, the device where the manufacturer can use battery life as the upper limit for device life will win.

I don't know anything about chips and boards, but in the EU, a regulation will come into force in 2027 that requires batteries in portable devices to be replaceable by the user without special tools.