What stops an entity to dominate & control Cardano by floating multiple large stake pools

Hello Cardano community,
excuse me for being naive but I have a basic doubt.

As we know, Cardano was designed to work against the economic incentive where large pools dominate the system, by making it less attractive for a pool to become too big.

However what stops an entity (person, organisation etc) to dominate & control Cardano by floating multiple large stake pools ?