what of WiMax?

It was superceded by LTE/4G mobile broadband to which it is very similar, but seemingly slightly inferior.

What up WiMax

Of the major carriers in the U.S. only Sprint was really behind Wi-Max. It actually had a decent rollout in the D.C. area but it fizzled out once LTE became more established.

UC Berkeley has (had?) a WiMAX base station that staff or enterprising students could connect to with full campus bandwidth. When Comcast started some shit, my flatmate managed to secure some kind of uplink to the WiMAX network. On a clear day we got fantastic speeds, but during stormy or even foggy weather we didn’t have any connection.

WiMax is like the Betamax of 4G network technologies.

What of it? Irrelevant in the practical sense at the current time, as far as I'm aware. LTE ate its lunch.

It's pretty much everywhere in Japan. I have a 200Mbit device and pull down 30-40MB/s when I have full bars and I haven't exceeded my plan (then reduced to 200-250kbps).