the real question is how much time will it take for someone to grind enough credits worth selling, then flying around the population bubble looking for ppl to manually target and speak to, honestly, credit selling in this game with a transfer feature wouldn't make it much easier you can still spend days flying around without finding anyone. and what you think they have the will power to go around manually convo'ing every pilot they meet, knowing that most of them will probably report them.
i honestly find the ideas of gold selling in elite, ridiculous there is no niche for it, grinding is the entire game why would anyone that is currently enjoying the game pay more money to skip the very thing they are enjoying. there is no second avenue of time consumption like theme park mmos, you have your grinding and your end game, grinding funds the end game progression. but, elites end game is grinding so.. this is where the gold seller tidal wave prediction falls flat.
How much easier would it be to do all of that grinding in the ship of your choice fitted out like you'd dream of? Then you'll ask, why bother to do that when that is the whole game right now. Well for one, you see it all of the time, shortcuts are an internet favorite. People are already irked that you can grind up to the big ships in Solo, and then jump in Open and PvP like a boss in the biggest ship you can get. Add people that just buy a ship to that mix and see what happens.
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Professional Gold Seller are grinding machines. You must be aware of that. Hundreds of bots grinding out in Solo, where no one would be able to spot them, drop into Open fill up the Mules account, and back into solo.
Take the long view. Look down the road.
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Comms are coming. Right? Once there are General Comms, you're just one step away from Spam. And, the ability to openly trade credits would be all it takes to get this game a Pay-to-Win label. (it's a silly comment, but it will/would happen).