Look for those profiting from the status quo to do everything possible outside of the market to stop it.
The purpose of the system is what it does. The purpose of seemingly all regulatory institutions is to gain and maintain power for the tribe in power.
These trucks are illegal to sell new in the states
Japanese producers aren’t designing these vehicles with American second hand JDM import buyers in mind
Kei-truck manufacturers make no profit off this US uptick and consumers are at best irritated and at worst paying import fees because their domestic producers refuse to meet their needs and force them to cough up more cash for a vacuously useful and environmentally harmful oversized utility vehicles
Markets can work, this is a clear example of it breaking down (for the US) and a sign the government should step in to steer the - arguably flailing - market
You point out US consumers might be annoyed at bad local options and are looking elsewhere then suggest that this is a failure of the market when in fact it is this market action that permits the consumer to find a better solution for their problems. All government can do if they "step in" is make this even harder.
You cannot Force a market.
What is your point? I am simply stating that you are overstating the actual market share of this demand. I don't disagree, modern trucks are comically too large but Kei trucks are not a response to it.