just curious.

also curious how different ranking systems for hex match up to ranking for chess/go.

I figure Hex must be the modern abstract that has the best shot at a legit and fully fleshed out ranking ladder.

100

Well ranking and rating systems are not the same thing. How many people have some kind of rating is generally regarded as a better measure of a game's popularity. I hear Hex is very popular in Portugal, but I don't know anything about a governing body or a ratings system there. There is a tournament at the MSO in London each year, and there has also been one in Paris in the Spring. There are, let me see, Game Center, Playok, Ludoteka, Boardspace.net, Tanaka games, and BGA that's at least six realtime servers, and LG, Gamerz, and BGA are turn based (BGA offers both modes.) Speaking of popularity, at the moment I post this, there is a real time 11x11 tournament scheduled in a couple hours on Ludoteka. The Java client app requires an older Java, which they provide a link to download. The time limit is 60 seconds to make all your moves with 7 seconds increment per move. So how about we invade and concquer?

Are you sure Hex is present on MSO? I don't see: https://msoworld.com/wp-content/uploads/2020/02/2020-Schedule-Published.png.

spartacus, around 100 know some strategy but the active players are less than 10.

The ratings are meaningless in my opinion. In fact they're meaningless in every game and they're not directly comparable. It always depends who you're playing with. In general yYou can always manipulate ratings by playing against weaker players or the players that do struggle against you for whatever reason.

Couple of years ago I even wanted to take part in MSO, but Hex was cancelled then due to lack of participants (I don't know if permanently or for that year)

SORRy my mistake, wishful thinking on my part. MSO has Twixt I believe but not Hex.

I asked them, they removed hex due to the small number of participants when it was present.

There are small Hex and TwixT communities in Japan. Maybe 10 semi-active and 20-30 rarely active players for each. I know a lot more people (200-400) own one of the games, but don't participate in any events or gatherings. I doubt those players are very strong unless they also play online, though.

Is it fair to surmise that the top Hex players on Little Golem are more or less the top in the world?  For what fraction of LG's games can that be said?

It's always possible there is some human who WOULD be the best human Hex player if they were to play on LG, but this is surely the strongest field online. I don't know much about most LG games, but the same could be said of Twixt and Havannah, and of course neither Go nor chess nor XiangQi.