1 GB storage on a phone won't be enough. Nor would 1 TB be.
It's how life is.
People with 500 mb hard drives can't imagine filling up a 1 TB drives.
Those with 1 TB wonder why they didn't buy 3 TB.
And once you have 5 TB of data, you say to yourself, how come it is still full?
It's just how it is. We keep what we need, we archive what we want to keep. We backup as we increase our data. And we can do more if we can store more.
People on 4 mbit internet with a small laptop screen ask me why I have an interest in 1080p content and don't realise my cable connection sucks down media in a matter of minutes. 500mb drive wont' be enough for me.
If you don't take 4k video on your phone, dont have a large library of music you want to keep around. Rather have offline storage for certain dropbox stuff than always downloading it over and over again etc.. then 32gb phone might be enough. Others might desire 256gb.
In the future if we have a 1 TB phone.. I am sure there are people who say 'i need 2tb, because i backup my macbook ssd to my phone ..' or whatever