You don't realize how incredibly difficult step 6 is.
6a. Fill your inventory with 0-9 stacks of dragon eggs.
6b. Head to an atm with a deposit sign.
6c. Craft (remaining inventory space - 9) eggs into emerald blocks.
6d. Craft your emerald blocks into emeralds one by one. Hold ctrl Q and drop them in front of you.
6e. Repeat 6c and 6d for 2 minutes 30 seconds
6f. Rebind your place/use button to a key on your keyboard. Increasing repeat rate in Control Panel > Keyboard > Speed > repeat rate.
6g. Hold the newly bound key to deposit your emeralds quickly
Repeat the whole process indefinitely.
You will be able to deposit as a rate of approximately 166,000/hour if alone and 333,000/hour with a helper.
Yhe theoretical upper limit is 720,000/hour. You probably won't reach this limit due to lag and human inefficiency.