DIDs have been placed on blockchains for over 10 years now. They don't really solve anything by themselves. DIDs are fine, decentralized and can build the open trust model you want. But specific DID Methods are always more constrained than the DID spec. 

BTW, Microstrategy said in the video that the first e-mail is signed by Microstrategy's keys. So, I am not just imagining this. 

I don't think the approach is terrible. It's just that there is no difference from what they are doing to a regular company-owned DID process. 

Nostr Follow Lists already created a more "open trust" model than any DID implementation ever built.