So I did a search on Cheap CNC, which is a surprisingly fertile field in technology today. Maker Faires are the modern version of the Dot Com boom, really. Check out Boingboing.net if you don't believe me. Gizmodo too. Tons of news on new technologies that make the iPhone look really passez. Most of them are being built in kitchens and garages by the underemployed. And commented on by people like me. And they're being built with hand tools (some powered). Combine all those interesting machinists with electrical designers. There's all sorts of things they can fix or improve and make.
On a related note, eventually we're going to be dealing with synthetic algal-based biofuels to run our cars because we don't have a large enough source of lithium for car batteries for everyone, just the 1%. Maybe not even them. Anyway, synthetic fuels will have different costs. Synthetic biodiesel is around $30/gal. at current prices, assumed to be scaled up to every town and city. Synthetic gasoline made from that diesel needs refining (cracking) to convert, plus lots of additives. And then the labor costs, etc, gets you up to probably $40/gal for gasoline to run in a modern car. Turn that into E85 by thinning with ethanol, which isn't free either, and you'll probably see that one around $25/gal. Pure ethanol E100 is probably $15/gal but will wreck your engine so requires lots of maintenance, particularly pistons, rings, and probably sleeves and valves and valve guides too. These are NOT CHEAP parts. And you'll probably need to do this twice a year. Really, the diesel is going to run the longest and cheapest. Most modern engines are gasoline, but its possible to build a multifuel capable engine based on a diesel design with fuel injection and sensors to adjust the process so you can run various mixes, key for modern idiots to run. Take your Civic or Camry and swap the engine for a small diesel. Swap the transmission to take advantage of that and driving 50 mph in overdrive gear on our putative real world speed limit in a seriously fuel-poor future. Rich people will probably drive faster. Poor people will do it too, but get pulled over and beaten to death for resisting arrest or unpaid tickets or whatever. You choose. The Highway Patrol will likely change their stance on speeding and what constitutes reckless driving so they can get better funding through the rich people they stop and