Right around the time of the poker boom several notable poker authors said that No Limit should be a “dead” game unless the players at the table were playing with invisible antes. At that time, during 2003-2004, there was so much money to be made in NL cash games even some of the more seasoned limit players switched over to catch the gold mine that was NL cash games. But if you really take a look at it closely there really should not be that much money won in No Limit if everyone would play optimally tight. In fact the game would be hard to beat with the rake if everyone played less than 20% of his or her preflop hands.
Of course there is money to be made in poker because rarely this is the case at a table especially at the lower levels. Players are commonly playing 30-40% of their hands. And because there are no antes in No Limit cash games you can literally play less hands than your opponent, be patient and have such a beginning hand strength advantage over them that playing tighter can almost show an immediate profit. It is different of course in tournaments where the blinds escalate. There if you play super tight you will be at an inherent disadvantage because winning more chips gives you an advantage. In a cash game the size of your stack is irrelevant and sometimes it is more advantageous to be shorter stacked than a loose opponent.
This is why some older players that may have less fundamentals and technical skill than their younger counterparts win more money in the long term. With age usually comes patience as well as more emotional self-control when things do not go their way. But the most important part of this conservative attribute is realizing that there is no need to force the issue in a cash game. And that is why you can win a lot of money versus a player that is tilting who is forcing the issue. If this tilter suddenly goes from playing 25% of his hands to 50% of his hands you are at a distinct advantage over him just based on hand strength. Add to that the propensity for his post flop bluffing frequency to increase and his random spaz factor to go through the roof and you have a very profitable situation. You can even go so far as to play slightly more hands against a tilter. Say you play 20% of hands when all things are normal. The guy who is losing goes from playing 25% of hands to 50% of hands. You could increase the amount of hands that you play to 30% and still have a huge hand strength edge over him going to the flop.
Be careful, however. You need to know which types of hands to expand to. Implied odds holdings like 5♠ 8♠ have little value against someone who is opening super wide because the chances that you hit and he hits at the same time are very slim. However hands like ATos or KJos go up in value as you can have the best hand at showdown without even making a pair.