I agree that boting is in and of itself a problem. I am certain that there are people logged into every server at this moment who actively violate the TOS, and some of those are in fact engaged in rmt.
Before SE can act they need proof of wrongdoing. Your reasoning seems more based on the idea that if you accuse someone of boting it automatically follows that they are guilty, and SE is then required to act on your accusation and issue a ban. If SE doesn't do so then you reason that they don't care, or are being profit minded.
It would be a very bad thing if SE banned people simply because another player thinks they are guilty of something.
You are assuming that behavior X automatically leads to behavior Y. A person who wanted to pay the sub on 8 accounts could legitimately use the mechanisms of the game to make gil for themselves in that very same way. Prior to the leve gil nerf this might have been a legitimate way to rmt, but now I don't think that's the case. You would make way more gil, and spend far less real world money farming the right items with a single toon.
I knew a six-boxer on my server in XI. He was pretty famous and a perfectly nice person who just enjoyed the challenge of running his own 6 person parties. If you didn't know him you could certainly look at his 6 characters and call their behavior suspicious, but he wasn't actually doing anything wrong or violating the TOS.
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Its funny how in XI I remember people claiming that shell X was botting whenever they claimed an NM over us, but when you would tell them 'if you think they cheated call a GM' there was always some excuse not to actually involve SE in determining if they had in fact really cheated.
If someone claims an NM over you it doesn't automatically follow that they used a bot. If you accuse someone of wrongdoing with disappointment, anger, or jealousy as your motivation it's not only bad behavior most moral codes treat it as worse behavior than cheating in a game.
I know in XI some shells did bot, and some shells botted everything. This included NMs in abyssea that repoped in 5 minutes. That's pretty lame, but it's up to SE not us to determine who those people are and punish them.