1) The scale of the problem seems much lower on PCs because Windows and MacOS respect local regulations, Linux has an infrastructure to do so that works by default in some distros but not others, but overall the Linux market share is small and as is PC WiFi adapters are more often sold in country-specific variants with hardware restrictions than the chipsets in routers are (and usually have lower hardware Tx power limits). Overall, the architecture of WiFi is such that it's rare for a PC to make these kinds of decisions anyway. If it's an infrastructure mode network, the AP dictates channels.
2) FCC enforcement is, in general, rare. It usually requires specific complaints from commercial broadcasters in order for the FCC to respond. In the ISM and WiFi-specific bands, enforcement is extremely difficult because enforcement methods like radio direction finding are inherently difficult for the frequencies involved and even more difficult because of the high noise floor and large number of sources in urban environments. Even if the FCC allocated significant resources (which they do not), it would technically be difficult to enforce these regulations.
The FCC has closed more than half of field offices and laid off half of the enforcement staff over the last ten years. They have eliminated most of their field enforcement teams and now only have teams (perhaps only a handful, they don't say but the best public info I've found suggests 5) based out of the DC area that have to fly out. It's been very frustrating to see the FCC eliminating enforcement resources these days, but the reality is that enforcement has become far more difficult and less effective over time due to advancements in the technology. Direction finding FM pirate stations is technically pretty easy and something the FCC is very effective at (especially since FM broadcasters inform the FCC promptly). Just about everything else... fat chance of the FCC doing anything about it unless they can do so at an organizational/regulatory level (e.g. fining manufacturers or large scale operators). At the field level it's just too expensive and unproductive to try to track down individuals who have configured their WiFi routers in violation.