And the number keeps going down because... That's good marketing. IEEE rebranded 802.11ax as wifi 6 because... Marketing. They can do it too.

So, the IEEE has an actual norm for marketing speak.
Which, honestly, ought to happen more often.

If I'm not entirely mistaken there is still some basis to the nanometre number, it just doesn't refer to the actual smallest feature size or gate pitch anymore. Basically in the mid-2000 Dennard scaling stopped working and ever since the nanometre numbers are "made up". Dennard scaling was how most progress was made by just shrinking transistors. But that doesn't mean just because Dennard scaling doesn't work anymore there is no progress, it's just harder to achieve. So the semiconductor manufacturers just continued naming their fabrication methods as if Dennard scaling still worked. So basically a modern "3nm" process is equivalent in some way to what would theoretically be possible if you had an actual 3nm process.