Unfortunately even the T-series has gone 100% on the integrated battery now, which IME is the thing most likely to need to be fixed. Aside from that, agreed.
Swapping the integrated battery is a 5 minute job, so if you are not planning on hauling around multiple batteries, it's not a major issue. I haven't really used the hot swap capability my T440s has, even though I have multiple. Maybe if they had a separate charging dock for the batteries...
Did you try to open T470/T480 (maybe T490)? There are awful latches which are integrated in case, so quite expensive to replace.
Oh no, that's sad to hear. I have T460p with completely replaceable battery and T470 with half-and-half. Didn't expect they would be go 100% baked in.