In practice, the reasons why these don’t come standard dispite having been around in this form for over a hundred years tend to come down to boring things like adding a lot of mass high up on the ship and adding a not insignificant amount of maintenance for the crew in extange for a marginal improvement in fuel for a few types of ships.

They do have some effect no doubt, but you can achieve the same gains by just dropping a few knots off the ships speed with no other changes.

More to the point, they don’t really provide a pathway to zero emissions, just a few percent reduction. As such the focus is going to need to be on both alternative fuels that can be made carbon neutral or by reducing the need for them in the first place, which either through direct reductions is intercontental shiping or by prioritizing overland low tariff electrified rail along most routes. Build out zero carbon ways to get around the two major landmasses that have people on them and you just need ships to take the shortest path between them as well as the outlying islands.