Some get built eventually but it can take several years between planning board approvals and construction financing and permits. Especially if they redesign it again. Those eventually happen, but COVID messed things up.

For others, yes they are scheming to get wealthy without having any actual plans to build. Buy a forgotten site for like $250K, put together plans and get planning/zoning approval for a big tower, and then sell it for $5 Million saying “Fully Approved for a 25 story tower”