However, you can still purchase any land put up for sale via NFTKey.
"Earning speed" describes the amount of CLNY generated per day, which is determined by how many upgrades have been built.
"Earned CLNY" does not necessarily mean the land will come with any CLNY already generated, as the seller may have removed it before selling. It will still generate CLNY each day, it just probably won't come with a bunch of CLNY stored up.
No matter how many players join, there will only ever be 21,000 land plots for each blockchain's colony.