Think you're being a bit pessimistic there Jezza
The Cepheus engine used a dedicated supercomputer and solved for heads-up limit poker. Multi-player NL poker is orders of magnitude more complex.
GTO is designed to be unexploitable, not maximal - so it doesn't make the 'best' decisions in terms of beating particular players, it makes the 'best' decisions in terms of what the opponent might do against them. So unless you're playing at a table full of GTO bots, there is still room to play 'best' against a particular fish
There are of course solvers out there that people can use to develop strategy, and maybe even prompters that can be used to advise in game - however, in general these aren't that difficult to detect. It would take a pretty sophisticated computer set-up to have something that is virtually undetectable, and well beyond the ability of most players to implement. Of course, nothing is impossible, and anyone with a working bot (or array of bots) isn't going to publicise it too much. Similarly the poker sites aren't going to publicise it too much either. On balance I think it is a risk, but I'm playing a fair bit of online poker these days, up to 0.25/0.50 NL and I'm not seeing any particular evidence of prevalent bots - or if they're there, they're very far from unbeatable.
I think the new business strategy at PokerStars is interesting - they're obviously trying to reorient the site towards recreation players. That's bad news in terms of rakeback/bonuses etc, but probably good news in terms of attracting fish. Not sure how the balance will ultimately settle, but the new features are definitely aimed at the gambler not the strategist/grinder.
