Disagree. This is basically impossible to do for multiple reasons.
The main one being that Motability isn’t offering insurance. RSA Insurance does. They introduce the guidelines as to who can drive what. That’s one of the reasons why used cars are a non-starter as well. A used car will inevitably rack up more garage bills than a new one. You can mandate Motability as much as you want, if RSA pulls out everyone is screwed.
Second, who’s going to check that the car you bought is “eligible”, in terms of insurance class and horsepower restrictions etc? Like them or not, they exist and they exist because RSA wants them to exist. They’re a condition for them to insure your car.
This isn’t going to happen, purely from the insurance side already, and you very much can’t “mandate” an insurance company to insure everything that gets left at their doorstep.
Do i think the scheme is fit for purpose?
Yes. And no. For us, it is. We don’t have a wheelchair, we don’t need adaptations, meaning we can drive hatchbacks etc no problem, we’re not confined to the “big SUV category” as others are who need space for wheelchair, scooter and similar. For us, there’s still some choice left on the scheme (new 308 looks great, so does the DS4, Focus, etc). Prices/AP could of course be better, but still, the choice is there. I would argue on the other hand for people with maybe 3 kids and a wheelchair, no. The scheme is not fit for purpose anymore. It MIGHT become better once the Dacia Jogger makes it to the scheme, which i’d urge Motability to get as quickly as possible – but at this very moment, for anyone who needs a big car with extensive modifications.. no.