Tbh I think people are reading a little too much into the image. Could their motivation for just showing the Monorail and Space Mountain to hint that they're safe "as is"? Perhaps. Occam's Razor tells me they're the more iconic parts of TL so they just chose that for the graphic to represent the announcement.
Space Mountain as a concept and the Monorail are safe. That I can 100% guarantee. The idea and name of Space Mountain isn't going anywhere. Everything else is fair game.
That being said, I sincerely hope that aide from the obvious People Mover demands, the other priority will be to drastically update Space Mountain. I know people enjoy it, and I enjoy it as well, but the ride itself is....slow and dated. The ride is just gradual dip and then sharp turn at a max speed of 30 mph. It will look even more dated and borning once Tokyo opens theirs up next Spring!
I don't think we will get a clone of Earth Rise. As Jake already brought up, we have yet to see a clone of any major Tokyo Disney ride make its way over here. I don't think Earth Rise will by the exception. BUT I could see Disney giving Vekoma a call to make DL's own "Earth Rise" if that makes sense. It wouldn't be a clone of it, but they could get close to some of the more thrilling elements of it. Heck, they might even include the upwards tilt track as Vekoma does make the tilt coaster after all. If they wanted to go the cost-efficent route, they could always keep the dome as is and then expand the showbuilding containing the coaster a little bit towards main street to allow for more space.
I said this before many times, but DLR is way, way, WAY overdue for a proper new coaster. WDW has been getting them left-and-right while DLR hasn't had a brand new coaster since 9/11 with Screamin'/IncrediCoaster. Before the Disney purists get angry about the change, the ride would still hold true to Walt's vision: A high-speed thrill ride through outer space....it would just be fasterr, more thrilling, up-to-date, and (At least in theory) just as accessible!
I know this post is long, but I wanted to get this off my chest: I want to see drastic change to everything. This is their chance to knock it out of the park with a brand-new TL. I want everything to be amazing including Space Mountain. If not Earth Rise, then give us something close to it!