VTI (Vanguard Total ETF) is $600B + VTSAX (Vanguard Total Index Admiral) is $489B. QQQ is another $480B AUM.
So we're easily talking about $Trillion++ for funds that are described by this post. (VTI, VTSA, QQQ alone). With dozens and dozens of more funds that are participating in this whole "passively buy stocks" scheme being discussed.