Going to explain this in bullet points:
1. RMT Send tells because they have Product (Gil/items plus they do sell Endgame Duty Wins).
2. Researching the enemy: they make product from Dungeon grinding 24/7. In 30 days a 80 man team of RMT/Bots can amass 1.2+ "Billion" Gil.
3. RMT/Bots then camp base useful items. Shards, crystals, clusters, fleece, tufts, gold, darksteel, etc... only mats useful in most synths and then craft.
4. They then proceed to inflate prices on new HQ gear and drop base mat costs to control the market. The less people able to craft or attain their level in crafts/gathering the easier it is to frustrate newer players and have them think about spending that 30$ for 10 mil. just to catch up. Thus you have the gil buyer.
5. Regular players who know this try to cash in on it thus keeping the market bad for everyone else: only benefiting the few players who are already way ahead in the gathering and crafting game.
I want to see them change the market to balance player time vs money.[I have every job 50 and all my crafting / gathering jobs are geared. I have no problems making gil but I see many new players struggle to catch up even in one class. I can play the gil game... they can't. To me that's an insult to the new lv. 50 player.]
Spiritbinding is a perfect "example". 45 min to get 6 materia. The New player has to spend 27k at Mor Dhona to SB a set of 6 items. They obviously can't craft it yet. By Market Board: Grade 3 sell for 3-7k, Grade 4 = 20-200k (crafting/gathering materia). On average however your usually only going to make 25-50k profit in 45min. That's the same as running Brayflox HM for 45 min doing speed runs except you get raw gil from monster drops plus additional stuff you can sell.
Now if you balance time vs money it'll make it harder for RMT/bots to sell product because regular players wont be forced into that stress situation of not being able to catch up even just a little bit.
Selling to npc and making gil by raising the amount base items are worth, and making limits on the market board for how much items can be bought for can fix this.
*You know those items on the market board like a bat fang for 200mil? Gil buyers put items like that up so gilsellers of whom they bought from buy that item from their retainer. The gil buyer makes 200mil off the marketboard and the gilseller makes their cash in real life. And SE can't do anything about it because it wasn't a person-to-person trade. The buyers excuse is they "got lucky".
Your not getting rid of RMT or bots. Statistically impossible. You can however make it easier for everyone to be self-reliant. Your still going to have a player market because humans are lazy. I could farm 50 grade 1 materia in 2 hours while glancing my TV no problem but instead I buy the materia for 2-3k a piece just to save me two hours so I can grind with my friends.
Time vs Money will keep player economy moving.
Making the game Human realistic will reduce tell spam because they're going to have 500 billion gil with not enough players to buy in order to keep business afloat.
1 US Dollar is worth 6.21 Chinese Yuan.
So when one person buys gil like 30$ for 10 million G... they make 186.3 Yuan.
In perspective: 100 Yuan can buy a meal for 3 at McDonalds.
A team of 80 gillsellers sitting on 14.4 billion gil make about 3,353.40 Yuan or $540.00 USD per Year.
However to an average person in China... $500 USD is equal to one weeks salary.
This means these guys are botting out the wazhoo in order to turn profits or something shady is going on... like there cracking free character accounts on FFXIV, or both.