If we cut down all these pesky trees we'll be able to enjoy the beautiful flowers of the forest. Where does that leave the forest though? The net has a problem with noise, not space.
You are right - harddrives are so cheap today that we can trivially host all the text anybody cares to write.
On the other hand, for any given query there is only 10 spots on the first page of google, and I really rather not have any of them taken over by spammers.
If all those who make websites to peddle ads were forced of the net, maybe there would be a space for those who have a passion and love to create.