I sort of agree, but I tend to get attached to books, and trying to do a cull ends up an excuse to read some of them again, and the cull is never quite as brutal as it should have been. A bit like having tons of bikes, probably only a small number get used regularly, but there could always be a time to ride any of the others, so they can't really go.
Of course, there's lots of reasons to keep books.
Ones you've loved, ones you may yet come to love.
The everyday well thumbed references, and the others with obscure nuggets of wisdom yet to be revealed.
Then there's the ones you like to lend out, whole shelfuls that visitors will borrow for long dark nights in caravans with patchy wifi.
The books you shared with your own children, which the next generation might enjoy.
The books given by dear friends, no longer seen.
The old penguin editions of novels purchased by now departed parents, but perused by this curious child.
Even the books written by ones own parents.
All those, and of course the journals of various lifelong enthusiasms.
The technical manuals necessary for work, and on and on.
The Internets OK for some stuff.
But somehow, until its been written in a book it doesn't have the same heft.
I'm always trying to prune the books, and then like you say, you end up sat there reading them.
Oh and don't get me started in on
maps... 
to that! Chin chin! 
