Not really. You can count on a gas pump existing within some distance of a sparse population. You'd be surprised how hard it is to find an outdoor "public" power outlet when you need one.
That's a little bit of a stretch. You can walk a 5gal tank all sorts of places roadside assistance won't go, though that's largely a reflection of corporate policy than physical inability.
Also it's way harder to get someone to give you a charge if you run out due to circumstance in the middle of nowhere whereas pretty much anyone will give you a gallon of fuel if you're truly out.
Having that number on the dash saying 600 miles left as I enter into remote-ish areas is so comforting. So much so that I've already ruled out upgrading to the Lightning and instead am targeting the Powerboost, which keeps my range, increases my fuel efficiency (though not by a ton) and has a world of possibilities for utilizing the battery for heating a camper or a toy hauler -- I don't have one of those but if I had a Powerboost I might consider one for snowmobile camping or ATV camping.
I'm not sure how a Rivian or the new F-150 Lightning would compare to a more typical rugged off-roading vehicle (e.g. Raptor, a TRX, or a Rubicon), let alone a truly heavy-duty one (Land Rover Defender, H1, or G-Class).
Maybe bringing some gas + a generator would be a viable contingency? At the expense of some weight, of course.