Having worked in the industry at that time, there were 2 main reasons they did it like that
batteries were quite unreliable and failed often
mfgrs couldn’t afford to have one year warranties and send out field replacement units for a battery
And the reasons they stopped doing it…
batteries got better
battery contact failure was higher than battery failure.
replaceable batteries compromise waterproofing
I think they should still be replacible, but they should have better connectors that are sealed off from the rest of the device. It costs a tiny bit more to do that engineering though.
I don’t know if it’s even borrowing, really. If you borrow my drill, I can’t use it. If you torrent a movie… Like… You’re seeding, and more people can use it!