People for whom a system works will always defend it, or not even realize that it is there (or that things could be any different; that it is the only way the world could ever be).
As far as survival of the "fittest," I think the famous line is that C. Darwin never said or wrote that. And the trouble is that people get human notions of "fittest" mixed up with what natural selection does. Humans are a social species, so any appeal to "every man for himself/ fu** everybody but me" is not about evolution or any "eternal truth." It's just human BS that works at this stage of history in the westernized world (where you can screw people over and then disappear into a crowd. If you do that in a small village and you end up in a stock in the town square).
Enron was big internally (and externally) promoting cut-throat competition, and that didn't in the end work out very well for Enron, or the rest of the country. But the leaders loved the idea; not sure why so many people worship that.