The way I see it, if the pension fund has less money there's less to manage and also less to gain from. If the people flee to private investments, they do not necessarily flee to Blackrock.
Isn't this change about the public pension, which is not a fund at all, it's simply a transfer from workers to retirees? Blackrock has nothing to do with that money, except in that if the money becomes insufficient, people might privately invest in Blackrock products to make up the difference.
Sure the workers are screwed in favour of retired people but the fund is increasing with this change.