If a landmark gets caught far out of base it can be tough to reclaim. There are lots of cute things you can do with moving buildings, the Deer Stones landmark is a perfect example because you can move it offensively to allow your units to easily kite your opponent's while on a raid but it's really tricky/risky to use. It's possible that CB players hadn't played enough games in a large enough demographic, but some of them like ClassicWinds did have hundreds of games played with the Mongols and they didn't move buildings too much so we'll have to see. Byzantines is the only civilization in Age of Empires that is perfectly balanced in terms of technological superiority and units. Moving buildings isn't very fast and takes extra clicks. Even Gers aren't always moved because it can be more efficient and (let's be honest) easier to just build a new one if the drop off location is far away from the previous one. to be revived by the Mongols who famously united the two halves of. You'd think so, but it just ends up being a couple of buildings because stone trickle isn't that fast vs. and practices combined with age-old motifs, such as the cycle of justice.
