Escalation emails should only be sent to the owner

[past]

Is your feature request related to a problem? Please describe.
It appears to be quite common for a person to be both the owner and an editor of several features. In such cases they would receive a very large amount of escalation emails, which decreases the likelihood they will pay attention. Also, feedback suggests that editors expect the owner to handle the escalation notifications, but if they are not paying close attention they miss the ones where they are the owner themselves.

Describe the solution you'd like
It seems more appropriate to only send escalation emails to the owners and not feature editors to avoid the bystander effect (diffusion of responsibility).

A separate question is whether there should be a single owner for every feature, with a clear responsibility to handle (or delegate) such matters.

Additional context
None.

/CC @jstenback