Chess is possessed of nearly infinite defensive resources. – (I have forgotten which master it was who said this around 1940. Richter? Steiner? Rauzer? Teichman? Google can’t find it.)
Bobby Fischer certainly believed that Chess is possessed of nearly infinite defensive resources, and would take amazing risks (such as the Black side of the Poisoned Pawn Najdorf) on the assumption that if the chosen tabiya was not mathematically unsound, he would merely be required to out-combine his opponent.
Computer chess has lent support to this intuitive utterance: lines which were once discarded as highly inferior have been promoted in stature in modern times as defensive technique has grown by leaps and bounds. That defensive technique should flourish as the game matures is natural: if we had not seen it in the previous century in English Draughts (Checkers), we would recognize the pattern from the game of Baseball, once predominately batting but nowadays predominately pitching.
In my Denver Chess Club game this week, my opponent was an autodidact with some fanciful notions about a favored defense that he and his brother have worked out on their own. Without guidance, they have nearly discovered the Hippopotamus independently. In last month’s tournament, my opponent won an upset prize against a Category 2 player with this defense. His handling of the position fared less well against me, but it shows how natural and universal the principles of this sort of defense are.
Side note: There’s an interesting blog posting from a few years back that attempts to determine how many logical games of chess exist. By logical, the author apparently means something like reasonable or likely. The presentation is not at all rigorous, but the intuition expressed therein is attractive.