I don't agree with the statement. Holding your own keys is significantly easier than running an email server and keeping it updated. However, a counterpoint is that holding your own keys does put more on the line if you screw things up.

I don't run my own email server. But I've had enough trouble with spam filters wrecking my day when I try to do email through my own domain that I worry a similar dynamic could be created with bitcoin: if we rely on a diversity of service providers to give us bitcoin services and then they get mergered and we only get a few big providers and then things are gated. Also: we live at the mercy of our email providers. If google and microsoft refuse to let your emails reach inboxes, good luck on getting any business done in this world.