It makes perfect sense because the original net cost was only $5000. So even if you used the only example ever of Tesla charging more after sale (when AP/FSD used to be a little more expensive- a practice they found was a failure and abandoned) you'd only be talking about charging 6k for it.
So if you sell it for that you might well get a lot of buyers in an amount that is almost 100% profit for the company.
In contrast- nobody would actually pay 15k for it so you'd get $0 in extra revenue, let alone profit.
This is the same reason Tesla doesn't charge $18,000 to add FSD after offering it for 6k pre-purchase.
The original cost was 10K difference. So buyers would have to fork over at least 10K. But I would say a higher number would be more fair, so 15K is a number I am throwing out there. Maybe 10K for the acceleration uncork and an extra 5k for track mode and the max speed boost.
You keep referring to some mystical $5k number. This number did not exist. Owners of performance models did have the option to return their free supercharging incentive for a 5k check. If you are an M3 AWD owner with free lifetime supercharging, then I would support the option for you guys to return that incentive for a 5k check as well.