Patent law is fucked up at the moment. 28 years is far too long. Should we fix it the right way, yeah, but that's not going to happen, so given the choice between not having any RAM for 30 years or letting China fight it for me, I'm definitely going to not care if China flouts patent law. The system obviously doesn't work well so who cares?
Reminder: America was literally founded on ripped-off British patents (let's start with the cotton mill, among others). Developing country steals patents from developed country, film at 11. Now we are the developed country.
Now you throw in the fact that you've got cartel behavior from 3 companies who have near-complete control over the supply... and I'm supposed to cry for Micron here? Trust me, they'll be fine. Maybe they should push their capex back up instead of collecting rents (which is definitionally what a patent does).
If it is a legitimate patent, it is supposed to allow them to choke supply.