Um, hikikomori are a hotbed of creative works, though. Your entire premise is false. I don't know that you could get reliable statistics proving this claim, but Japan likely has the highest number of creatives per capita of any country in the world, and a ton of them are NEETs who spend their time drawing fanart or writing trashy webnovels. The vast majority of this creative work isn't commercially successful, of course, which is part of why they're NEETs.