3. A top online player once told me some stuff about the top players playing poker to such a high standard that they played almost perfect always taking the correct lines so that they were not able to be exploited. If you knew exactly how this player played everyhand then surly you must be able to exploit this.
This is going off the topic completely, but I am going to address it for completeness sake.
First, the top players DO NOT always take the perfect GTO (Game Theory Optimal) unexploitable lines. There are two reasons for this:
1. It is not always possible to know what the best GTO line is. Poker is far too complicated for that. It is true that certain spots are 'solved' - e.g. optimal shoving ranges when relatively short stacked. But it is still the case that the vast majority of spots in poker when you have more than 30 big blinds are unsolved.
2. Even if poker was fully solved, the top players would still not take the optimal unexploitable line. They would instead choose to EXPLOIT their opponents by taking a line that takes advantage of their opponent's leaks. If their opponent worked out what they were doing he could adjust and in turn EXPLOIT THEM. Any deviation from the GTO line is, by definition exploitable.
Easy example... if you think an opponent is a calling station then you EXPLOIT him by never bluffing and value betting a little thinner than usual. This would not be the GTO way to play - you are
supposed to always have a certain amount of bluffs in your range. But you would make more money remembering never to bluff a calling station than you would if you dogmatically continued to think, "I've GOT to have a small amount of bluffs here, to balance my play. So I will make a bluff this time in order to keep myself balanced". You'd still win money in the long-term from this opponent if you followed a perfectly balanced GTO strategy (a balanced strategy will automatically make money against an unbalanced strategy, unlike in a game such as paper, scissors, stone in which a perfectly balanced strategy will only ever break even). But you would make more money if you deviate from 'optimal' strategy in order to exploit his tendency to call too much.
Of course, by deviating from this GTO strategy you make yourself exploitable in turn. So if your opponent realised that you had adjusted to him, he could counter-exploit your adjustment by never ever bluff catching vs you. Now you'd find that your value hands were not getting paid off, and your opponent was
crushing you by folding. So you would have to start bluffing again.
This is what poker is all about of course! Adjusting to your opponents, then adjusting as they adjust to your adjustments. And so on.
Second, you are incorrect in your assumption that if someone is playing a perfectly optimal and unexploitable strategy then if you know what that strategy is you can still beat them. You cannot do so. The best you can achieve is to break even in the long-term through also choosing to follow a perfectly balanced and unexploitable strategy.
For example, imagine you and me get to the river in a hand. I have bet every street and my range is uncapped and polarised (i.e. I am either bluffing or have the effective nuts - so almost all your hands, even the relatively strong ones, are now bluff catchers). The pot is £1000 and I now jam all-in for exactly £1000. You are pondering what to do with your TPTK hand. Now I do something bizarre. I tell you my exact range. And this range is made up of 66.6% combos of hands that beat you and 33.3% of complete bluffs. And for whatever reason you KNOW I am telling the truth. Plus, you can't get any physical tells on me or anything like that, so you cannot work out which part of that range I have
this particular time. What should you do? Call or fold?
The answer is that
it does not matter what you do. Regardless of your decision, I have WON THE HAND. If you fold your EV is of course £0 and I win the £1000 that is in the pot. If you call then your EV is also £0 because you will win £2000 once for every two times you lose £1000. If your EV is £0 when you call and there is £1000 in the pot then that £1000 must have gone to me.
So, in this situation even though you know
exactly what my strategy is the best you can do is to break even on the river. Which means that I win all the money that has been put into the pot before the river. Even though you know my strategy, you cannot 'win the hand' once it gets to the river in this exact situation.