Earlier quoted context omitted.
you don't get to resell the land when you're done with it, so it loses its value as a speculative investment. also the government gets a window whenever the lease ends to decide to do something else with the land (eg, build a train station).
I guess it depends on the term of the lease. You do get to sub-lease the land when you're done with it. The terms could even include an up-front cash payment that looks not dissimilar to a sale. This creates some value as a speculative investment, depending on how long the lease is going to last.
that's an interesting point. whether or not they structure it as an upfront payment, there's still an opportunity for people to grab a ton of leases, do nothing with the land, and essentially arbitrage the government rent. I guess you couldn't really eliminate this behavior, but you could limit it by the shortening the length of the lease term. of course, if the term is too short and the government is free to pick a different lessee next, it might be uneconomic to actually build anything.