Petro-chems are still the most efficient and easy to use power source, as it retrains energy potential throughout transit with minimal hassle on the part of the handlers. Nuclear is very nice for energy generation, but it's not popular with most of the populace, and is not the easiest stuff to safely handle either.
Gasoline is just... ridiculously good as a fuel to the point I think most people don't actually realize just how good it is. It basically checks every box that you could want a fuel source to have, including ones most people don't think about.
Like, for instance, what happens when you spill gasoline? Yes, it's toxic, but it's not THAT toxic. You can clean up the spill with a basic absorbent, and the risk of fire is actually quite low. Heck, you can literally toss a match into a barrel of gasoline and you know what happens? The match will get snuffed out once it hits the gasoline and sinks in. Gasoline is more safe to handle than the typical batteries in normal cars. Spill gasoline on your hand? OH NO it's... oh right, mostly inert, wash your hands before eating. Spill a lead-acid battery on your hand? Well, off to the ER with you, maybe you can save your hands, oh and now have a risk of lead poisoning.
Then you get into the weight vs power aspect of gasoline and it just... well, blows pretty much everything non-nuclear out of the water. My understanding is that for the same given mass, gasoline provides more power than batteries, though that same mass will take up more volume than a battery will. The only things with better power to mass ratios are things like Uranium, etc. when used in nuclear fission reactions, and, well, let's be honest, nobody really wants fission powered vehicles.
Also, being a liquid is like, a perfect form for a fuel. Solid fuels are a pain in the ass to handle and transport and then use in a vehicle, requiring complicated mechanisms to feed into things. Gases are even WORSE, needing systems to maintain constant pressure and seals and if there's a leak things can get nasty quickly. Liquid? A bit harder to transport than solids, but leaks are easier to manage and you don't have to keep the same level of airtight seal going at all times. Plus liquids can use very basic pumps and pressure to distribute without needing complicated gas systems or the complicated mechanical systems a solid fuel needs.
Seriously, there's a reason gasoline and diesel became the standard fuel choices for vehicles. It was the fact they were straight up the best things we've had, and still have, for the job.