Nintendo should start adding some bright, easily visible message to the system UI that indicates the device is permanently restricted so that buyers doing a cursory check would see it. It should be as obvious as a theft-bricked iPhone.
I believe they have a financial incentive to not do this. If buying a second-hand switch is perceived as risky, then sales of new switches will be encouraged. Of course this would cause a switch to depreciate even more when you buy it since it would suppress the market price of a used switch. But I'd wager most people aren't considering how much they could get from selling their switch when they're considering buying one.
Alright I'm claiming ignorance here; I didn't know you had to play an online game to know. Figured it would tell you as soon as it came up assuming you were near wifi (which even then is a big assumption.) My mistake, hadn't thought it through.