When I hear "replaceable battery", it makes me think of the days when packing a spare battery was a viable alternative to bringing a laptop charger with you (I don't think any MBPs were like this, but Powerbooks were). It's funny how the Overton window has shifted.
This procedure looks doable and relatively low risk for technical people, but it's not something that my mom can do while sitting at a Starbucks
These days the battery lasts so long you don't have to bring a second battery with you and your laptop could realistically be charged by any phone charger overnight.
You also have the option of battery banks. As long as you can replace the battery when it wears out, thats all that matters to the average user.
I remember borrowing my sibling's iBook G4 battery while sitting at the airport back in the day. You'd just push the grey button on the bottom face and it popped out.
I can flip my notebook over, pop the battery out and put a new one in within 5 seconds. That is replacable.
I also replaced a macbook battery once, with a hot air resoldering station (to soften the adhesive) and a metal bucket filled with sand nearby in case it catches fire (the battery was balooning and bending the aluminium frame out of shape). The whole thing took nearly an hour. Ultimately it was also replaceable, but this was needlessly painful.
It's still an entire procedure. You have to remove the trackpad to access all the cells. Most users aren't going to be confident doing that to their $2000 laptop, they will continue doing what they do with glued in batteries today which is hand it off to a technician and playing the flat rate apple repair fee.
Pretty good was the first unibody macbook (open latch with one finger, remove door with two fingers, remove battery with two fingers, done):
This procedure looks doable and relatively low risk for technical people, but it's not something that my mom can do while sitting at a Starbucks