It's the same attitude you may have noticed that come from people who defend socialism but when confronted with the flaws of the Soviet Union, Maoist China, or Cuba will claim that those were, nor are, not under real socialism, but something else (tsarism, in the case of Russia).
It's the same attitude you may have noticed that come from people who defend libertarianism but when confronted with the flaws of Somalia will claim that those were, nor are, not under real libertarianism, but something else (anarchy, in the case of Somalia).
The truth is, people game any system. They want that cushy job, that fat pay check, the easy life. Any form of organization whether it's corporate, government, non-profit or otherwise end up serving at least three distinct interests. The one they're supposed to serve, sure. The actual people working in that system, they all want theirs. And finally the system itself, the government wants to expand the government's powers.
Incentives are flawed. Checks and balances are flawed. But perfect is the enemy of good, because the alternative to not keeping those forces at bay is exploitation. Inevitably, when there's no power structures they create themselves, anything from gangs to warlords to conglomerates to oligarchies. The idea of an egalitarian society where everyone is equal and power doesn't concentrate is like a world with gravity where matter won't clump together.
There's a reason why Churchill said "Democracy is the worst form of government, except for all those other forms that have been tried from time to time." I think the same can be said of capitalism, there's hardly any problem finding faults with it. The problem is finding a better system that works in the real world with real people and not some idealized form for an idealized people. Ideology is always clean and academic, the actual implementation is always messy.