Unfortunately, the rental companies (or at least Hertz) don't seem to agree. My very first Tesla I ever rented in early 2023 had one. Every one of the dozen-plus EVs I've rented since has not.

That said, I haven't really missed having one. I use mine in my personal car frequently when road tripping, but mostly opportunistically (to get some free electricity to avoid paying for more expensive electricity at a DCFC) and not as a mission-critical way to add range (although once or twice, it's been a little iffy and being able to plug into even a 120V outlet overnight has made getting to a faster charger the next morning a good bit more comfortable). So far on my rental car trips, even the more rural road trips, I haven't encountered being in a pickle where a mobile charger would have made a major difference. Not to say it couldn't happen or that Hertz shouldn't provide them, though.