It had been in the works for a while, but now it has formally been adopted. From the article:
The regulation provides that by 2027 portable batteries incorporated into appliances should be removable and replaceable by the end-user, leaving sufficient time for operators to adapt the design of their products to this requirement.
Phone companies actively design those things to get worse with time. Especially when you hit the two year mark it usualy drastically decreases in a very short period of time. And even if they didn’t its pretty normal for a battery to get worse after two years of active use with constant charging and unchanging. Especially because we tend to not care for our batteries that much.