> The question is whether it'll ever get out of cities? While storage is constantly getting cheaper, but is it feasible to map and update the maps sufficiently for a cross-country trip?

That's certainly the intent with Waymo Via for trucking, and we drive multiple routes today including say Dallas <=> Houston for beer [1]. The video at [2] includes some footage of the trucks on a highway.

[1] https://www.ttnews.com/articles/waymo-ch-robinson-driverless...

[2] https://www.youtube.com/watch?v=Lon1vRv2wQ8