One aspect of reliability is simplicity. Simple mathematics. If there are fewer parts, there are fewer things to go wrong. Yet the internal combustion engine, not to mention the rest of the car, is anything but simple. A typical 6 cylinder engine is a system of hundreds of parts. In addition, the parts have very complex timing interactions as the RPMs vary from idle speeds of 800 to 1000 rpm to maximum running speeds of 5000 to 6000 rpm. Across the range of speeds, the relationships between the moving parts require precise control to operate correctly, which is difficult to do in a purely mechanical system.
Amazingly the auto industry has evolved with the necessary manufacturing precision and repeatability to meet the requirements of making reliable engines and vehicles that operate 5 years without major failures. I have managed to own and operate 2 cars that were 10+ years old and in generally good running order when I sold them.
Electric cars, on the other hand, have essentially 1 moving part. The rotor of the electric motor. Hybrid electric vehicles have small displacement fuel engines that run at constant speed and only turn on when additional battery charge is required. Pretty simple.
Electric cars also have a lower cost of fuel per mile driven based on the extremely high efficiency of the conversion. Gasoline combustion conversion efficiency is less than 20% with most of the energy being wasted as heat. This could be greatly increased by newer technology like opposing piston engines or wave combustion engines. The best gasoline fuel cars cost 12 cents per mile if you use 30mpg an $3.60/gal. In town mileage costs are a lot higher. Electric cars are estimated to get 3 miles per kilowatt, which depending on where you live could be about 4 cents per mile.
Electric vehicles which have little or no maintenance would have little or no costs associated with the running of the car. Combined with lower operating costs per mile the electric vehicle becomes an extremely attractive option. If you have solar panels on the roof of the garage, the “fuel” cost could be zero after the cost of the solar power system costs are recovered. At a guess, that could take about 5 years. But it’s a really cool concept.
Light weight vehicles, at half the curb weight of the current of the 3500 pound Chevy Volt, are also likely to cost a lot less. What we need are a bunch of new companies, with a bunch of new lightweight electric and hybrid vehicles. If the vehicles can be profitably brought to market, they would create huge demand.