Clearing mines is no an insufficient solution because it is pretty much all you can do. You have pretty much have two choices, you can either clear them OR leave them. If you leave them, that is a much more insufficient solution than clearing them. They need to be cleared, so this is the best solution available.
Removing mines may not usher in a world of total peace, but it is a worthwhile goal and a necessary step to disarmament and a less militarized world. Mines by their very nature are durable, and there are even active minefields left over from World War One. Some nations, like Laos, have so many landmines, it may take centuries for them to be totally removed. So it is a sufficient part of an overall solution.