Fun story regarding Hex. It nearly reached what I would call a "mainstream" audience with the movie "A Beautiful Mind" about John Nash starring Russel Crowe. Unfortunately, the Hex scene was cut from the movie! You can watch the cut scene at https://www.youtube.com/watch?v=pTZ3nn2Bge4
Possibly, but my takeaway from COVID is that games like chess and go (which experienced a bump in popularity during the lockdowns, and have since been dwindling back down) are not merely gems waiting to be rediscovered, but instead appeal to outdated tastes in gaming, and are unlikely to be replicated given market realities. You need approachability for game-one beginners, you need vivid and eye-catching visuals, you need progression systems and content drips to keep players hooked, you need monetization to milk the whales, etc.
Or Spirit Island at high difficulty?
Dominion is also great, and in its simplicity literally invented the deck building genre. But it, too, is too artificially complex to become immortal, even before you get into its 16+ expansions. The proliferation of the deck builder genre also makes it less likely any individual game is going to be deeply studied.
Credit to games like YINSH, anyway, that specifically try to appeal to competitive, deep, and mathematically simple foundations. They just don't have what it takes to thrive in the age of monetized bright flashing lights.
With limits on expansions and other rules, it is possible to get Dominion competitive enough to study games and optimize for turns, the original isotropic had a decent ranking and rating system (RIP and add’l shoutout for their implementation of the Innovation card game):
Whether they become "timeless classics" and get a stream of discoveries or not I think is mostly down to chance. It's more about what we let them be in our lives than their inherent qualities.
Ah, I miss the old Isotropic implementation....
It's a turn-based abstract space fleet battle coming to your browser in 2026. It's already playable over the internet w/ time controls and ratings. If that interests you, join the discord for updates and playtest invites!
There are some cool abstract games out there, but they're not super popular. Abalone was mentioned in another comment here. Octi is another cool one. Some like Azul or Patchwork have a light theme but it doesn't really affect the rules, mostly just an excuse for the piece design, which I think puts them in a similar category to chess.
I'm not sure I'd say we won't get another deeply studied game. I mean, if we're comparing to chess and go, it will take hundreds of years to really know if any modern game has that staying power, let alone remains interesting to analyze. But I do wonder if we'll ever get a game that's both deep and popular.
The popularity of RPGs, TCGs, and expansion-based games suggests to me that a lot of people really like feeling a sense of immersion into a "world" that's constantly revealing new "content", rather than discovering new variety within an existing system. Maybe this is just a stereotype, but I also feel like there's a synergy this and a similar vibe prominent in stuff like fanfic, where people like to engage in this sort of generative building on some core ideas. The "pure" or "cerebral" gamer who is really interested in the ramifications of a fixed ruleset is somewhat more rare. Also there are so many games out there now that even cerebral gamers may be tempted to explore new ones rather than digging deep into familiar ones.
This is just to say that maybe some existing abstract games are actually deep, but in order to know that, we'd need people to take the time to analyze them and explore them. Maybe time will tell.
There is another aspect to the thing I didn't mention but you did: It may be that the sheer amount of interest in board and video games at large is more to blame for the lack of deep abstracts than is the inherent lack of appreciation for them. In sum total, there are probably games out there currently that could be mechanically fit as a successor to chess or go, but with so many competing games out there (both cerebral and otherwise), even the cerebral gamer is unlikely to pursue them singlemindedly.
Most games are quite modern, including some designed this year. And they have Homeworlds!
Master of Orion?
Here's a wealth of turn-based strategy out there, especially in the retro days.
Moo3 I never played, mostly based on the recommendations and reviews of other moo players.
I played civilization through civilization 3, and I muck around a lot with free civ, which is kind of hackable.
There's also remnants of the precursors, a Java remake of mu1 that I found very hackable. I've been able to run it from IntelliJ and hacked the source code.
This is a journal that tracks a lot of new abstract stuff: https://www.abstractgames.org/
Notable recent releases:
https://boardgamegeek.com/boardgame/352238/turncoats
https://boardgamegeek.com/boardgame/2655/hive
Even if you expand the search criteria to include video games, there just aren't many deeply strategic discrete-time games that weren't invented centuries ago and have players online at any given time. Here I exclude games that are perpetually changing and/or have strategies locked behind progression systems and paywalls, such as TCGs and virtual deck builders. The very few exceptions I found were niche Discord communities around games like Tak, Hex, or Advanced Wars.
When did we as a society lose the appreciation for these things? I get why including a component of dexterity in strategic video games (e.g. RTS) is to take full advantage of the medium, but all this in conjunction means we are very likely never to see another deeply studied cerebral game like go, chess, shogi, mahjong, etc. arise ever again.