Nothing in medicine is as straightforward as that. Most cancer treatments end up wiping out or suppressing many different kinds of cells, and a temporary suppression of white blood cells is considered an acceptable side effect. AIDS will have to be cured. A strong immune system often attacks donor organ cells, so the immune system is intentionally weakened. We may eventually develop solutions for all three issues, but I don't expect it to happen in our lifetimes. Heck, I predict we'll be cloning body parts in labs to obviate the need for anti-rejection meds long before we learn to fine-tune our immune response.
Electric cars can have ICE's strapped onto them, and it works really well. The Chevy Volt, for instance, is perfectly designed to handle the situation you described. It gives you 52ish miles of all electric range, so you can commute and grab groceries and do all of your normal driving on pure electricity. And for various road trips, it still gets 40-ish MPG for hundreds of miles without any electricity needed.
It also needs zero fancy charging infrastructure. Have a regular US household power outlet anywhere in your garage or home exterior? Then you have everything you need to charge it up every night.
We could easily eliminate 50+% of US personal vehicle emissions, simply by putting 2013-era PHEV technology into every single car /SUV / truck, and getting people to plug them into regular 120V US household outlets overnight. Even rural folks would benefit greatly from getting 1 or 2 free "electricity gallons" every night.
Pure EV's are obviously ideal, and way cooler. But even just a little bit of electricity in a PHEV goes a long way to reducing/eliminating emissions.
