The efficiencies of scale switchover point is probably a lot closer to hand than you think. VW's ID.3 is already cheaper than all comparable gas models of the (outgoing) similar Golf, and just about all of the German auto manufacturers have been not-so-subtly saying that they expect that all of their EVs will be cheaper than their comparable models with other powertrains in the next couple years.

China has sub-$15k equivalent EVs today. Cheap EVs are certainly physically possible even with today's scales, and partly it's just the catch-22 perception hump of "EVs are only for early adopters and luxury cars" (for both consumers and manufacturers) keeping EVs from hitting some scale benchmarks to push them cheaper.

The used market still isn't showing a lot of EVs, but that seems to be that statistically most EV owners keep their cars for longer. That's an interesting statistic, that maybe points to reliability on one side, and a possibly very different replacement rate on the other side. Which is to say that the average EV first owner is currently keeping their vehicle for 7-10 years rather than the 4-5 year replacement rate that has been of typical of ICE vehicle sales. (If EV owners were only keeping their cars for 4-5 years, as you suggest of some hypothetical "HN bubble" that would be a lot more of them on the used car market, and in turn fewer complaints of the high cost of EVs. The long first life of an EV is also keeping the costs up and affecting depreciation rates.)

Could be. I'll believe it when I see a $15K well equipped EV with 150mi+ range, no subsidies, no "fuel savings", no bullshit. We aren't there yet, to put it mildly, and given that battery production capacity can't keep up with demand, it's unlikely that we'll get there in the near future. But CNG is doable today. Pipelines are already there, fuel production capacity is basically inexhaustible for all intents and purposes, and existing manufacturers could easily adapt existing models of cars to the new fuel while they keep using the same facilities, equipment, workers, and dealer network as before.

I'd love to get an EV one day, when the pricing is less nutty than it is today. But it has to be economically viable for me. Right now it's not.

Ah yes, I'll just pop down to my local car dealer and pick up a $15k natural gas vehicle...

That's actually far easier to do (if there's demand) than $15K EVs. For an auto manufacturer, very little cost: replace the gas tank with a CNG cylinder (cylinder can be manufactured cheaply if economies of scale are in place), use the piping able to withstand the pressure, use slightly different injectors. Done.

Why every 4-5 years?

Beats me. How old is your car?

One is about a year, the other is close to five years.