Because it does not work on it's own. The IBLT compression is just a way to check whether a data (transaction) is part of a dataset (transactions in mempool) wh

Because it does not work on it's own. The IBLT compression is just a way to check whether a data (transaction) is part of a dataset (transactions in mempool) when collision is low. For this to work, the mempools must be almost same. Like I said, syncing unordered trustless distributed system is a difficult problem. Suppose, engineering implements a method to do so among nodes, it will by definition be a part of the way they network but concept-wise are a part of the consensus layer.