I'm not saying that it's a net loss, nor that even if a net loss that it isn't worth it. But there is a cost there, and you are shoving it away on your quest to regulation instead of looking at it and deciding its worth.
Yeah, incorporating some product standards is going to raise the cost of all units sold, which represents a loss to the buyer who hoped to get the product at the cheapest possible price and was either willing to take perfect care of it or tolerate it not being fully repairable if it were broken. But that's OK, because when regulating something the most important person to consider is the median user, noth the clumsiest/unluckiest nor the most skilled/luckiest.
If the median user buys a car expecting to drive it for 5 years, and there's a >50% chance that it will suffer some damage to some major functional component during that time, it would be pretty inefficient for said damage to cost more to fix than the cost of replacing the whole car, unless cars were to become so cheap that it was actually cheaper and better to scrap them - perhaps thanks to some breakthrough in large-scale 3d printing technology or so.
That's what happened with computer keyboards; it used to be that they were fairly expensive and if someone spilled coffee into one it was worth dismantling, cleaning, and re-assembling, but then cheap membrane keyboards assembled with increasing levels of automation brought the price down faster and faster, and today you can get a PC keyboard for something ridiculous like $10. A few fetishists still pay out for old-style IBM Model M, but most people will just replace a damaged keyboard.
But while cars remain relatively expensive and hard to dispose of, it makes sense to minimize the economic losses stemming for a lack of modularity and repairability across the market as a whole, rather than seeking to minimize the costs for the stingiest buyer.
What if the chance is actually 1%? What if the cost of repairing it is bigger than a new car? What if, as you said, cars got cheaper, but not so cheap to be disposable? What if making if repairable has the side effect of making it less durable?
Just nobody upthread is asking any of those questions. It's not circular, it's a plain old and boring cost vs. benefit assessment to be done over government intervention.
Competition from non-Cherry keyswitches have forced Cherry to drop prices, such that nearly identical keyboards from 2008 now cost a quarter as much. Cherry was valuable for proving the technology in the premium market, and Cherry's competitors were valuable in bringing the prices down and driving economies of scale to make mechanical keyboards basically a "no brainer" purchase now.
