I’m missing something.... When I was in my teens, my brothers, friends and I and did a few engine swap outs, mostly to squeeze more power under the hood and some of those swap outs even involved ones where the engines and the car bodies were different manufacturers. Now things are simple... there is a battery, an electric motor and a body. Surely somebody can figure out what to swap around and jerry rig to make something work, no? What is so difficult about it... is it simply impossible to find any components? No electric cars in the auto wrecker yards yet? Are we headed for a day where cars are just thrown out when the batteries are done?
I think the biggest challenge with your idea is software.
While the basics of battery cells and electric motor are fairly simple, these new vehicles have zillions of lines of computer code.
It will take some $eriou$ engineering to make parts compatible.
Can’t say it won’t happen, but it’s not like putting a 350 Chevy in a 32 Ford chassis.
“there is a battery, an electric motor and a body.”
And a computer. A computer, like ICE cars is tuned for general use, not for optimum performance.