So, does anyone ever cash out with these big heists? Like is there money leaving the ISK ecosystem in cash? I get that you can measure ISK since it is pegged to subscription costs that are solid objects that can be traded or destroyed, but does anyone heisting 22k of eve online ships actually ever turn that into money at that rate? Who's the buyer, vs WoW goldfarmers?
Trading ISK for real money isn't allowed by CCP. You are exactly right that describing an amount of ISK as if it was worth some amount of USD doesn't tell the whole story. It's likely that if the market were truly bidirectional, ISK would be worth less USD than it seems now.
The exchange rate is based around PLEX: an in-game item that can be exchanged for subscription time. People who want to buy in-game currency spend real money for PLEX, and then sell it in the game to other people.
The only way to do so is if you find a buyer IRL, but you're probably looking at taking a big hit on your profit. People can buy an item called PLEX for real money, which they can use in-game for a month of subscription OR they can sell it for the in-game currency, so you're already competing with those that are willing to spend real money on in-game currency.
But it's a frequent issue in other MMOs, where these companies will set up bot farms (or even pay people to play) to earn tons of the in-game currency, then sell it online. Officially it's not allowed by most games, but it's only illegal if you get caught.
For one character, but they don't mind (if not actively encourage) people paying for multiple characters. Although I'm not sure if they decided to crack down on multiboxers or not.