Note: Some wild assumptions here.

Crafting
Player skips crafting.

Gem Crafting
Player skips gem upgrades.

Item Selling
Assuming that the average price of a Legendary/Rare item is $10 and after a daily play session of 16 hours, only 1 such useful/sell-able item drops.

After a month, the max total revenue from just selling items is at most $300.

Gold Selling
Let's assume that the gold price is $1 per 1M. Within 16 hours, the player is able to collect 500k gold. So within a month, the player is able to earn an additional of $15.

Commodity Selling
Wildly assume that 1 Magic Item drop every 5 min. In 1 hour, you get 12. In a day, you get 192 items. Finally, in a month, you get 5,760 items which salvages to 5,760 Magic Powder and 1,152 Rare Teeth.
Assume 1 Magic Powder costs 1K gold and 1 Rare Tooth cost 5K gold.
Total sales = 5.760M x 2 = 11.52M = $11.52

Grand Total excluding Gems
Grand Total = $300 + $15 + $11.52 = $326.52

So are these calculations crazy or the $1k miracle Guide is more accurate?