Cheating and RMT exploitation has hit a new level of ridiculous.

[Jojoya]

Banning in waves is often the strategy other MMOs use. It has worked relatively well for Blizzard that used ban waves psychology. Enough players felt like they got away with it, got attached to having their cheated stuff and then banned them while removing it. Worked really well during Warlords of Draenor when there were several major ban waves during that expansion in the run up to the release of Legion.

You're assuming only lazy players bot. Ban waves work well for them but they're not the only ones botting.

Most botting is RMT and a ban wave isn't going to deter them. They've got no problem starting over because it's how they make money and the new account is just an operating expense.

That is false. Bots always had similar movement and you can tell who is a bot if you observe them for a bit. Not only that but if you teleport a player to the GM jail after you become suspicious of them you can pretty much confirm that they are botting with confidence.

If you want to fight botting you have to make the cost of purchasing accounts higher than the profit. Otherwise, being banned for botting is just a cost of ''doing business''. If you ban bots every few months you will NEVER EVER solve the problem this way because it will still be profitable.

The reason why they are not taking action is that they are cutting corners with CS. CS is expensive and investigating reports manually is time-consuming. In WoW classic I was banned for botting, I didn't bot. They used an algorithm to flag accounts as suspicious and banned them.
Plenty of legitimate players got banned but that was acceptable collateral damage because CS would be more expensive.

Pang Tong was correct about it being an arms race. That's part of why Blizzard ban waves are so far apart - they study the bot behavior to develop counter measures. Once they're ready to deploy the counter measures, they do the ban wave. The bot programmers then set up their new accounts, figure out what the counter measure was and find a new way around it. What's achieved through code can be circumvented by other code.

Making the cost of purchasing accounts higher than the profit has the potential to drive legitimate players out of the game. They're going to lose a lot of players if subscription prices were jacked up to $100/mo. That's the balancing act that game developers face - disrupting the bots without negatively impacting the genuine player experience.

If a game company wants to get rid of RMT and its bots, it needs to focus on the RMT customer. RMT stays in business because there's no penalty to being a buyer. SE can shut down one set of RMT seller accounts and another one will appear because the customer still has money they want to spend.