This is targeted at people who mod cars for fun, the kind of people who swap an LS series V8 into whatever. It's not at all intended for DIY conversion by non-experts of regular commuter cars to electric power.

It's neither sensible or sustainable for mass market use. Installing this motor in most cars would require multiple days of work plus custom fabrication. And then where do you put the batteries?

Manufacturers are happy to sell crate motors just to pick up a little extra revenue but it will never be more than a tiny niche market for enthusiasts.

It's undeniably more materially efficient to re-power serviceable vehicles but people get their the panties in knot over safety so I doubt the "reverse glider" approach will ever gain a big foothold in the light vehicle market. It would likely be targeted by legislation that makes it economically non-viable if that were to happen.

Considering that the venn diagram between "people who profess to care a lot about safety" and "people who profess to care a lot about the environment" has a pretty massive overlap I look forward to the inevitable dumpster fire as people are forced to reconcile that the tradeoffs exist.

Furthermore, a ton of ancillary stuff has improved so much over the last 20+yr that the cumulative difference is quite noticeable. Few people will drop "new Mitsubishi Mirage" money re-powering an '03 Civic.