Thanks for sharing, this was actually an interesting short read.
Since i was curious about the fee difference that caused so many to switch i did some digging and found this article. It also serves as a nice companion piece to highlight how Fidelity lowering their fees lead to Vanguard making those changes in the first place.
If i see this correctly the massive switch was to go from 0.12%-0.14% expense ratio in the Investor class funds to the cheaper 0.09% in the institutional class. And now everyone pays 0.08%.