With the DMCA, the pro-copyright people have to play a game of whack a mole. It allows entire site like online manga readers to exist in the first place.
The only reason manga readers exist at all is because a reasonable alternative does not exist.
If you could download, legally, that sort of thing for a token fee, not like the $0.99 download that finally made online music scales work, the demand would drop quickly.
Why spend hours trying to torrent something when for a nominal fee you can get a legitimate copy in seconds?