> Had this really not been done before? Apparently not on land. Ferries are an ancient idea, both for crossing water bodies and for traveling along them. They are fixed routes, of course, but that’s mostly because the shore is fixed.

Historically, not true for the “trekschuit” in 1632. For that, the shore didn’t exist before the route was envisioned. https://en.wikipedia.org/wiki/Trekschuit:

“The first trekschuit 'sailed' in 1632 between Amsterdam and Haarlem and could carry 30 passengers. The trekvaart or canal was dug in a straight line to facilitate an easy pulling process and to guarantee the shortest route”