Because I don't think charging is a "major inconvenience." It certainly isn't for me.
Yes, for some edge use cases EVs aren't there yet. Regularly traveling hundreds of miles in a day for work in the field, visiting multiple locations, sometimes off the beaten path, etc etc etc - yeah, I don't think EVs are the right tool for that job yet when "time is money". If this was the problem I was solving for, I'd probably buy a plug-in hybrid (which again, is basically what you're describing building in a Frankenstein sort of way
).
I've put 120,000 miles on a Model S in 4 years. Most of it in a round trip ~100 mile commute where I leave with a "full tank" every morning, plug back in when I get home, and never think about charging at all. The exact opposite of "major inconvenience".
We've also done a few big road trips all over the Western US. Even in my relatively short range by modern standards "about 200 miles real world range" Model S, driving 400-600 miles a day, I'd not call charging a "major inconvenience" when it comes to leisure travel. I need to stop every couple hundred miles anyway, and even if I didn't need to, my kids sure as sugar would. So we stop at chargers, empty our bladders, get some food, stretch our legs, whatevs. To be fair, I did eat a lot more Carl's Jr (what you east coasters call Hardees) than I would have otherwise - pretty much every supercharger in the rural southwest is at a Carl's Jr - but again that's really only moderate abdominal distress... not "major inconvenience".