It had to do with memory and storage limitations on computers back then. It didn’t make sense to store two extra digits for the date when that space could be used for other data. It affected pretty much every system made before a certain date. https://en.m.wikipedia.org/wiki/Year_2000_problem

Just coming from a civil engineering/construction perspective, the straight lines are probably more about alignment. In these kinds of buildings (and considering US zoning laws that require a certain amount of parking), sometimes the alignment is critical to ensuring the building, parking, and drive-through fit. Straight lines are easy to measure, draw, and check in the field. Not to mention the actual way these 3D printing concrete machines work. The ones I’ve seen online are on some kind of track, and these ones are no different. From the looks of it, they’re kind of set up like those cranes you see at shipyards: https://youtube.com/shorts/igQ9G_Brkl8