The minesweepers were an idea that seems not to have worked out too well in the past. They have their place, but I understand Navy has considered other means of dealing with the mine threat.
The old amphibs are being phased out in favor of the new ones, "old lamps for new".
During the Reagan years when the Navy was escorting tankers through the Straits of Hormuz and the Gulf, the means of dealing with mines was letting the tankers go first so that they would hit them and not the escort.
We keep saying we don't need minesweepers because we have a deepwater navy. And yet we spend a whole lot of time in areas that could be closed off very easily with a few mines. And we're doing away with the resources that defeat them.