TLDR: It’s quite simple. The return on investment of buying a boost has to outweigh that of simply buying multiple accounts. It doesn’t. Not even in the first month. It’s far more lucrative to buy multiple accounts and have the bots level themselves.
Let’s say a boost cost twice as much as the sub fee, which is the best case scenario for bots using boosts. $15 month sub, and $30 boost. EDIT: Regardless of the region, the boost will still be at least 2x as expensive as the sub.
At 70, let’s say you can farm 1000g a day as a botter. This number doesn’t really matter, but for simplicity, let’s make it 1000.
It takes roughly 7 days for the bot to get 58. Leveling to 58, you make 100g per day on average or 700g total. Leveling from 58 to 70, takes 5 days, and you make 500g per day on average or 2500g total. (Again, the time is likely shorter. These numbers are in favor of the booster)
Botter1 buys one account, and one boost. So, $45 total. He levels for 5 days, and earns 2500g. He farms for 25 days and makes another 25,000g. Total gold earned is $27,500g.
Botter2 isn’t an idiot, so he just buys 3 accounts instead of paying for a boost. Same $45 initial investment. He spends the first 7 days leveling to 58 and earns 700g * 3 accounts = 2100g. Then he levels to 70, and earns 2500g * 3 accounts = 7,500g. Then he farms the rest of the month, 18 days, and earns 1000g * 18 days * 3 accounts = 54,000g. Total gold earned is 63,600g.
Botter2 earned double the gold with the same initial investment, and next month, they’ll earn 3x as much.
BOTTERS WILL NOT BE BUYING BOOSTS!!!
PS: Even if I were wrong, which I am not, this is also a limited time service. In the long run, it won’t matter at all.