You have answered your own question, for you the answer is no. If you do not ride them, you do not need them! The possible exception being that you may need places to hang wet and muddy riding kit from your rides on the bike you do ride! Look if you love your bikes set them free! Find a good home for them, give them to somebody who needs a bike and feel joy in the process rather than the aggravation of dodging and hurdling them when you go to the backyard.

I own 10 bikes ATM and they all get ridden for considerable lengths of time throughout the year, however, as soon as one is not ridden often enough I find a new home for it!