We've mastered the wind and sun. The ocean is still beyond us. The unfront resource commitment to install the tech then maintaining a moving piece of equipment submerged in salt water.

Even structures with little moving parts like sea labs are abandoned after a decade or so because it just doesn't become feasible to maintain anymore.

Just like solar we'll start taking it more seriously when there's a promising feasible piece of tech thats easy to install and requires no to minimal maintenance. Remember this stuff is under water. Not easy to get to.