if you can't sell your land, you can always build stuff in top of it, and produce something to sell, so still worth it, in any case
You must spend more money to build that, and if you do, what kind of building will you build? If you build something that people don't like it, so they never come to your building, and the price of your land will be decrease.
there is one thing that people will always want, and they need forever
foods
this is the answer, build something that provide some special foods, or even a small supermarket, in a strategic zone, and you are done