You're thinking way too narrowly. EEE doesn't require a specific plan -- if you look at the history of Microsoft engaging in EEE, you can see it's been much more experimental than you're suggesting.
It's basically Microsoft saying "Here is a thing that looks like it might in some way eventually be a threat to our business model and/or we can make some money off of it -- let's get our hooks in now and see what happens, we have the money to do it."
But again, copilot does not get their hooks into open source any more than it gets their hooks into code in general. And they're not doing EEE against "code".
EEE doesn't need a specific plan but it does need some kind of target standard. Getting into an emerging market, without specific kinds of integration or malfeasance, is just competition.
It's basically Microsoft saying "Here is a thing that looks like it might in some way eventually be a threat to our business model and/or we can make some money off of it -- let's get our hooks in now and see what happens, we have the money to do it."