This is a brilliant and lively discussion that probably didn't happen when Eve was in early alpha, simply because people didn't know how or if it would work.
What we do know now is that very early on a sandbox environment is going to need a lot of sand and some sink holes to create further demand. This analogy is getting dark.
CCP did at the very beginning of Eve, which is when we should be looking at not 2010, but around the 2003/4 years. They needed to do it as player capacity and module limits made resource mining a lot slower than it is today, with fewer items to build too. They don't need to do it in the same way as they have the player activity.
PLEX trading isn't an Isk injection or faucet at source, it's relocating existing Isk supply from one place to another. It may lead to people working that little extra to get their own plex but most chose overtime and pay for their account sub, cheaper and faster in most cases.
Ultimately the game will need AI NPC's to serve as faucets for the player base, be it mission content in the form of blow me up for currency or move this stuff to my mate for money.
This will mean they don't have to have a closed market money supply which will need hand holding forever.