I would have easily traded settlement management for land vehicles and flying ship around planets.
If they aren’t doing land vehicles then it’s most likely the same reason they don’t do them in their Fallout games. There’s some interview that got posted here (this site, I don’t think it was this thread) a few years ago where Todd Howard says the reason Fallout doesn’t have vehicles is because their engine can’t handle the player moving that fast through the game world. It would seem that problem is still a problem with their engine.
It's more accurate to say it's a design limitation. If you watch a speedrun of their games, the engine clearly hand handle the player physically moving that fast. The problem is the cells don't stream in in time so everything looks glitchy. If they
really wanted to add vehicles, it's easy to see all the ways they could reduce the data streaming load. Instead of tracking every NPC and item in the cell at all times, they could simply unload those resources when they're out of view. They could drastically reduce geometry without sacrificing visual fidelity if they didn't dot their landscapes with so many points of interest and modeled interiors. But that simulation detail has become part of their brand so they elect for heavier loads and constrain the player's speed to compensate.
Without getting into the nitty-gritty, you're right, Gamebryo can handle vehicles. You figure out your maximum traversal speed and you optimise what and where as needed, tech application is driven by use case needs. The bigger problem has been flying "vehicles", like dragons and vertibirds, because of the much wider area to cover from high up, but that too can be addressed. And anyway, Skyrim had (slowish) horses, Fallout 3 got cars in the Frontier mod, Fallout 4 has a fully working (albeit not very polished) motorcycle mod, so it's not exactly a novel concept.
The main issue, however, isn't software design, it's
game design. Take the aforementioned Fo4 motorcycle mod for an example - it's a neat idea, but not very useful because the map topography and content density can't accommodate it, you can't go more than three hundred metres before you have to get off and fight something. To build vehicular gameplay, you need a giant map with open expanses, like the one in that Mad Max game. And then you need new gameplay loops to fill those expanses and keep that game "mode" as interesting as the pedestrian one, or you end up with Cyberpunk 2077's cars, i.e. pretty but dumb. You can't half-arse it (like settlements), you need a complete extra game mode so it's a pretty dramatic shift in scope. I
wish Bethesda bit the bullet and gave us the full Mad Max experience in their next Fallout (if we live long enough to see it), but I wouldn't be surprised if they kept passing on it.
On a somewhat related note, one of Fallout London's trailers has a guy riding a bicycle. Which proves Jeremy Clarkson was right about cyclists, they're a menace to civilisation.
