No, basements are not supposed to be dirty. And the only way to clean one is to dig in and do it.
If it seems overwhelming, break the job down into smaller parts. Set small goals, like cleaning just one corner. Then another corner, etc.
Make sure you get rid of things you don't need. Even if an item is useful, if you have no use for it yourself, it isn't valuable. Give items like that to the Salvation Army. You'll be helping someone who really does need the item. I find it helpful to make several donations as I move along with a project, instead of waiting until I am through with the project and giving one huge donation. It gives you inspiration to see the space getting cleared out.
After clearing the basement out, just vacuum and clean. Most things can be cleaned with plain old water or vinegar and water.