Doesn't have to be a perfect success rate... how about just something other than abysmal failure rate?

Asserting a sloganized refrain is not very convincing. Make a real argument. Here are some counterpoints to "big is bad" Neobrandeisianism: -Scale enables better economics for certain businesses which consumers and other businesses then benefit from. -Large size allows additional speculative cutting edge R&D funding which the whole world benefits from even if it never pays off. -Being big on its own is almost never a cheat code to permanent monopoly / monopsony lock-in, especially in the technology business. That comes from actual anti-competitive behavior or regulatory capture (which ARE the parts that should be regulated, rather than targeting or preventing size for its own sake).

The S&P point is more than a bit overstated and it also doesn't really matter? The subset of the S&P that's performing well will naturally get weighted higher over time, until the performance changes. It doesn't really matter if the S&P is driven by 5 enormous companies or 500 equally-sized ones. Whatever works at the moment is what gets rewarded with capital -- that's the point of the system and it's been more effective than any alternatives. Besides, it'd be poor investing practice to be literally all-in on the S&P.