Lets say there is 10 000 players
They mine and refine veldspar and sell trite it at 4isk each.
Then those 10 000 players make 4 more alts each and mine veldspar.
Now trite falls down to 0.8.
Each of those players are making the same isk as they did before but they are paying CCP 5x more subscriptions, so they are worse off than they where with a single account.