>clearly there's a huge market of people who would rather pay someone else to take care of it, than spend that same money (or likely more) on being a "provider

>clearly there's a huge market of people who would rather pay someone else to take care of it, than spend that same money (or likely more) on being a "provider themslves". There's a point that you might be missing. Similar to how you have people purchasing and maintaining powerful machines to mine bitcoin, you also have people using their spare HDD space or potentially buying dedicated storage to support the "distributed dropbox" system. The reason is that there is an incentive for doing so. You get paid for the storage/resources you provide. This adds to its scalability because any addition to the system is not only paid for but profitable.