While I can imagine that being a very likely scenario; I can also imagine a future where someone down at the local shopping mall will change the battery out for a Chinese compatible unit while you do your shopping. In the same way the currently do for phone batteries, screens etc.
It would be great for standard agencies / governments to get out in front of the electric car industry and demand standardised form factors for batteries and charging infrastructure. At the moment it would probably limit innovation too much though.
They don't really exist today, because contrary to what anti-EV FUDsters believe, there just aren't many EVs with worn out batteries yet. Perhaps there are a few, but the number of EVs written off in accidents (and thus making donor batteries available) is much, much greater.
There's a school of thought that past the warranty period, the traction battery is likely going to last the lifetime of the vehicle, by definition (in that when the battery dies, there is likely no economically sound way to replace with a new battery, so the choices are fit a junkyard battery or junk the car).