This applies to many different visas. The point is to ensure you are actually employed and not just here to subsist off of social services or working for illega

This applies to many different visas. The point is to ensure you are actually employed and not just here to subsist off of social services or working for illegal enterprises (i.e. organized crime). You can change jobs but the new employer must agree to sponsor you. Visas are not permanent residencies or citizenship. If you just want to tour the country or take university classes, get a tourist or student visa. If you did all the work to prove your "extraordinary abilities", you should be putting them to use. And yes, perhaps freelance work should be eligible for employment status but I feel that can be accomplished through some creative structuring of a tiny contracting firm. I can easily compare an O-1 visa to being accepted to a prestigious university. You proved you are smart and talented enough to be there but if you don't actually put in the work (get good grades/stay employed), you get kicked out so that someone else just as smart and talented can take your place.