I live on PDF books, especially those rarer books that you really can't even buy aside from getting gouged. Ironically the internet made rare books MORE expensive because initially those might have sat dusty on a shelf for years and the seller just wants to get some money back. Now? The internet makes specialty, out-of-print, and niche topic books so damned expensive because its become a seller's market with all the access to customers.
You used to find these things in used book stores for cheap prices, now they have all become big shit because of internet "search" features which blatantly take all the fun and art out of "book shopping" much like it destroyed the art of shopping for records
I think PDF has been a liberator to this boogie tyranny, in a way that Google books pretended it would be until Google Books just became another damned overpriced retailer..