It's not an infinitely long term solution but it's a solution that buys us at the very least dozens, if not hundreds of years before we run out of space. Because no solution is ever infinite, given that the Sun isn't, it doesn't make sense to consider something that will potentially work for a hundred years as a non long term solution. By the time that solution stops being long term, we'll have far more advanced options to buy us another century of time.
