Storage space is never filled. A new node joins, your node sees it and sends it 5 pieces of data, so your node frees up space to store new data. Data in the network moves like a slow river, old nodes receive new data and forward old data to new nodes. An eternal never-ending river of data that gets bigger and bigger with each new node.
If you want a chance to store new data to get paid for, you store old data first. This is an economically sound principle because the storage space in the world is growing more and more, and the tokens are a fixed number that does not grow 4.3 billion. The hypothesis is that people will want and appreciate them more and more, because they will be able to buy more and more eternal space.
Privacy. Security. Freedom