There's the theoretical side of "can we do better" in terms of engineering solutions, but that has to be weighed against practical limitations of "what are the implications."
As an aside, putting CO2 into the atmosphere is not inherently bad.
But let's say we come up with something radically different, some propulsion system that doesn't use a liquid fuel source, doesn't use an ICE, doesn't make "bad" pollutants.
Think of the industrial and environmental impact of having to replace just the 250 MILLION passenger vehicles in the US
alone. PLUS all the infrastructure. Every gas station. Every refinery. Every tanker truck. Every tanker ship. Every petroleum-fueled aircraft. Every petroleum-fueled boat.
Think of all the heavy industry required to do that. All the industrial pollutants, etc. How long would it take to offset that?
It's similar to economics of machine depreciation and value, efficiency, etc. Let's say you're a small business and you have to get a new machine to replace an old one. On one extreme there's Option A, which is cheap, maybe not super efficient, but in the short term.. the next couple years you can generate positive cashflow and be profitable. Then there's Option B, which is 10x more expensive... 15 years from now
when its paid off you might be making cash hand-over-fist from how well it operates. In the short term though, if you can't offset that up-front cost and you go out of business in 2 years.. it makes no difference.
Alternate way of looking at it from a micro scale.. let's say an awesome hybrid car is $50k. Let's say from your fuel savings, it will pay for itself in 5 years!
Makes no difference if you don't have that 50k up front!
Bottom line, eventually there's a point where no matter how awesome some technology or new thing is... the monetary or environmental or otherwise practical cost to implement it outweighs everything.
The biggest issue to oil dependency, IMO, is that it's not sustainable. Hubbard's curve projects the realities of this. We've seen the implications already in the US and globally with fuel cost spikes and the hit to the auto industry. Ethanol is sustainable, and practical.
Grip is a four letter word. All opinions are my own and not those of current or previous employers.