People lease land to build on instead of buy? That sounds absolutely bananas. (I'm not from the US so unfamiliar with your market).
There are examples of "leases of years" like Canberra/ACT in Australia, where all titles are for 99 year leaseholds.
They've started renewing them since the first leases were granted in the 1920s.
the 99/100 year lease is quite common in many Europan countries. It's not "exceptional" here
And actually you bring up another wrinkle, which is if you don't own the land underneath, there are plenty of lenders who also won't lend to you to buy a manufactured home, because they consider it to be personal property rather than a permanent dwelling (which they could more easily foreclose and sell)