Average salary in USA was 40k $ per Y in 2014. When employee see that he have a small hdd amount, he walks to supermarket and buy additional 1000G for 50usd (4 working hours) and forget about it for next 20-50 years.
Average inflation of US Dollar is 2.5%, 40k*0,025 = 1000 usd per year. Here is a problem!
IMHO, When blockchain growing size will be a real problem we found a solution. For example we can create redundancy distributed network database on masternode network. You can google for it. This solutions was described since '80.