There are several things that compound that - Storage price decreases near exponentially, while data usage also increases near exponentially, meaning that new data will always make the majority of your usage, no matter how long you and your users have been in place. - On Google scale, your are bound to have a lot of redundancy in data. Chances are that what you have in your Google drive, someone else has it. And larg…
I can't speak for anyone else, but I find this odd. Anything that is not unique to me, and can be downloaded again - I try not to have any copies of it taking up any of my space, local or in cloud storage. What I care about most are unique possessions - my (personal) photos, spreadsheets and documents. These are things I keep copies of both locally and online so that either could fail, but they still exist somewhere.