I see you're getting downvoted, but no one is bothering to explain.
First, the market in general works in the exact opposite way. You can invest a million dollars a lot of places; with enough luck and skill you'll earn a great return. Keep doing that and soon you'll have, say, 500 million.
But 500 million is harder to invest; you might say "stock X is really undervalued; I'm going to go long!", but if stock X has a market cap of 10 billion, you'll struggle to find 500 million in shares to purchase on a whim, and in so doing, you'll push the price up, and now it's no longer undervalued. Many investments that work for the guy with 1m don't work for the guy with 500m.
But if you keep going and keep being lucky (or skilled) you might end up with billions or hundreds of billions. Now you're basically fucked. Most possible investments don't have the liquidity or capacity to absorb the money you're trying to place. At this scale you aren't picking companies; you're picking industrial sectors or countries. You'll never make a great return like that. Plus you're being watched constantly; the merest rumour that you're about to invest will end prices soaring or crashing before you can move. You can "push the market around", but only in ways that benefit smaller, nimble players, not you. At that scale, your ability to be clever is basically nil.
Which brings us to the second point: Vanguard is an index fund. They simply buy an even mix of the shares that make up an index. Their entire strategy/promise is that they won't "push the market around" (which is the reason they have $3t under management; people explicitly looking for people who won't try and be clever).
So your question is "couldn't Vanguard do the one thing they don't do, because it can't work"? And the answer is no, it can't work, which is why Vanguard exists and has those assets.