You have never done any game development, it's obvious.
The step from single-player game to multiplayer game is not a simple upgrade, it's a complete shift in everything. It requires a completely different approach, not a refined version of the same approach.
In any non-trivial multiplayer game, the interactions between all the players matter, and the complexity of those is subject to combinatorial explosion. Poker being a relatively low-interaction game will not make this as bad as some others, but beating one person and beating a table of people is not the same system with a little more cycles, it quite possibly requires a different approach altogether.
It will be interesting to see the jump happen, but it is a jump, not a step.
AI beating humans at a game is merely a beta test. The real application will feed unending greed, which will never die.
Greed is a game.