Referencing a solver while playing (what people call real-time assistance or RTA) is definitely a problem in online poker and is always prohibited. Solvers however play in a fairly predictable way and poker sites can detect if people are using them, though I'd imagine imperfectly. Saying that 99% of online poker is vs AIs is a hilarious overstatement.
But it feels to me a bit awkward that I can't use all the tools that could help me play a better game. But of course rules are rules. In Formula-1 you can only drive a specific type of car. But the car-machine still helps you move faster. The car has a cockpit and I assume it is much computer controlled.
No we are not. Poker skills (even at a high level) go beyond live tells.
People spend thousands of hours trying to grasp it.
In a 100BB 6-max game in a single raised pot BTN vs loose player on Bb, who called your raise: is the J83r a good flop for a small bet? Maybe a bigger bet is the proper size? This is a simple question that has often a correct answer and the question is different for each flop, for each preflop spot and potentially for different opponents.
Now once you have figured out betsizes on the flop - go figure out which actual hands you are supposed to bet. Hmm, you should play most hands with mixed strategy of check and bet, but with different probability distribution so that your distribution of good hands / bad hands on the future streets after called is right on a variety of turn cards.
You can spend all life mastering that part alone and we are talking only about the first decision on the flop in single raised pot.
Tldr; poker theory is not something easy and quick to master.
There's certainly a part of me that wants to go thru this curriculum just to say that there's no way it could help someone to be better than an 'average player'.
Perhaps if the population on which the average is based is...the world?
Further, I disagree with your point that the mathematics of poker (implicitly top tier highest level poker) are not complicated.
(edit) to your top line point: > My intuition having played recreationally is that the absolute optimal move in poker is relatively trivial to calculate compared to chess/go.
While the branching factor of Go is between 10^250 to 10^361 (and chess is ~35), poker is 10^17 to 10^165 depending on the game variant: ""Thus, the game tree for no-limit has a much larger branching factor and is significantly larger; there are 10^165 nodes in the game tree for no-limit, while there are around 10^17 nodes for limit (Johanson 2013)" - Sam Ganzfried, Reflections on the First Man Versus Machine No-Limit Texas Hold ’em Competition
...though it's the hidden information component which ratchets up the complexity and leads to a game tree size that's many orders of magnitude higher. If you're curious about that, there's some great info here on other aspects which add complexity: stack depth, multiplayer scenarios, etc: https://poker.cs.ualberta.ca/publications/billings.phd.pdf
That said, I do agree with a relaxed version of the point you're getting at: some subset of high level poker skills can generalizable quite well to other jobs.
The future of online play will be catered more toward teaching, solving, and tracking hands, rather than playing competitively for profit. I recently started a side project in Rust to do just that, mainly for love of the game and desire to learn the language.
Hoping to release later this year and perhaps productize if it gains traction.
The prevalence is an open question, though. I imagine it's rather high since there's a huge incentive to cheat.
I'm trying to work on this myself in my spare time.