This is not even remotely true. Proven by the fact that when I started the game the overwhelming majority of all players had 1-2 accounts, some had 3, but mostly not logged in together because the third one was just a capital/jumpfreighter alt that would be used in very limited situations. And You could play a whole year without seeing anyone multiboxing like 4-5 or more ships at the same time to mass-mine or mass-pve or mass-pvp with them.
In fact, in the first 2 corporations I was, more than 50% of the players had only 1 account. Some had a second to support, like for scouting, scanning, tackling or fleetboost. And less than 5% had a third account, as said, for a capital or a jumpfreighter. And that worked perfectly fine. We did PvP, we did logistics runs and we did group-content actually as a group.
Still everything was absolutely affordable, people used T1, T2, Capital ships…
Mass-multiboxing is absolutely not nessessary to keep the games economy running.