However, it is false that soil cannot be created in human timescales. Gardeners do it all the time. It's called compost. A lazy human can make a cubic yard of soil in several months just by casually piling up green and brown material to rot down. An industrious human can do it in about two weeks with a sophisticated tumbler. You can even find tumblers with two or three chambers for staged composting. Most gardeners are in between; they build a pile and fork it over occasionally. Vermiculture is another option which gets worms to do most of the work. You can spread finished compost and plant seeds in it, and they will grow. If you want to get fancy then you can add sand, clay, gravel, peat, or other materials to create a specific type of soil suited to different plants you wish to grow.
We absolutely can undo the damage that humans have done to farmland. Plenty of people have bought a beaten-up plot of land and turned it into something spectacular. However, this takes time and at least a little work. The more soil you want to make, the faster, the more work it requires. The reason to protect what we have -- aside from not being a canker on the ass of the planet -- is to avoid all that extra work.
Oh, and while we're on the topic: creating and maintaining soil are skills we damned well better learn before leaving Earth. Yes, it is possible to grow some crops in hydroponics or other alternative systems, but they all evolved to grow in soil. You don't want to be without that option, because the others are all more finicky and space will kill you if it can.