bluGill

Electric motors are substantially cheaper (and simpler, and lighter) than internal combustion

Not really. There is a lot of metal - wires - in the electric motor. Retail prices on motors is a lot higher than the retail price on an ICE. https://www.grainger.com/product/WEG-IEEE-841-Motor-250-HP-15G092 is a 250 horse power motor for $30k. https://www.jegs.com/i/Chevrolet-Performance/809/19435110/10002/-1 is a 500 horsepower ICE (I think this is new, but the site also sells rebuilt engines) for $7k.

Of course with motors there are a number of different ways to built them at different costs. However they are not cheaper than an ICE and we shouldn't expect that they would be as there is a lot of metal in a motor.

the typical ICE has two electric motors already in it! (starter, alternator)

Sure, but they are small, neither one is capable of moving your car down the road at full speed (the starter might do it for 10 seconds but then it will overheat)

Last I checked the whole car scrapped for $250, and there is a lot more metal in the rest of the car (transmission, drive train..) than the engine.

Engines are worth more than $100 if they are rebuild-able. However the incremental cost to the automaker is less than $100. Remember, incremental cost does not include the cost of engineering, setting up the assembly line, or profit margin (which are all very expensive and raise the actual cost) - just the raw materials and labor to run the line.

While having a dozen in operation might be good, we need the ability to produce 100k of them in a month (including all the supply chain for that!). If the world gets into a war between any of NATO (US), Russia, China, India you can bet that missiles will be flying anywhere that is thought to be unprotected and so we need missile defense on all cities so that nothing is unprotected. The we of course changes depending on how is involved.

I said produce 100k in a month, not have them in stock. That is because technology changes. It is likely that when we (again not sure who the we is) needs this technology will have changed and so whatever existing systems we have are obsolete and useless. 100k systems would be enough to protect us (whoever we are) from today's threats, but they may be scrap when war comes.

But they do have an expensive electric motor instead of the ICE, plus an expensive battery.

They were never about hobbies. We were a niche that they were happy to have, but they never cared. Origionally it was about education (which has a large overlap with hobbies so they served well).

The downside could be something that nobody has imagined yet. That is the problem with change. I'm not against this, but I demand reasonable study. (but not unreasonable levels - vaccines and GMO have been studied enough to conclude they are generally safe despite people yelling more study needed)

Possible, but it may come with downsides you don't like.

There are lots of great choices. I personally like natural oil stones. For rough work I will go with india stones, then fine Arkansas stones for the finish. Others like waterstones but I find water messier as the stones need to soak (not all do, but some do). I find diamond stones are too course but maybe the ultra fine grades are good. Sand paper works well at 1000 and 2000 grit but gets expensive fast as the paper wears out fast.

all of the above work though despite what preferences. you will not go to hell or something for a wrong choice. In the end try soemthing and if it doesn't work for you try something else.

i do have some stones that won't sharpen my exotic wood working blades, but a kitchen knife won't be made of those.

Unless you are saving to something big in the near future it doesn't make sense not to. I have known many peohle to die young. I have known misers who died with millions in the bank. There is no point to money after death (at least not most religions, I cannot comment on yours) earn it, save a little for a rainy day and spend the rest.