I won't deny that it would provide Bitcoin with alot of capital. It won't increase the risk of capture. Over 19 million Bitcoin are already in circulation. These entities may hold more value but at a much higher average cost.
Discussion
I don't mean a 51% attack, I mean regulatory capture. Blackrock & friends may lobby to make themselves into the only approved way for institutions to hold bitcoin.
Ohhh. In that case it might be possible. But, there's also the matter of anonymity. That's already posing a huge issue. Even an autocratic nation like China wasn't able to fully get rid of or regulate Bitcoin.