Enormous sums are taken from markets as there are gigantic money flows moving between various categories of player.
Now to the question.
The first limitation is market liquidity daily in futures markets.
The next limitation is the number of markets available.
Then there is compounding.
Do the sums for compounding. This process cannot happen here because ETers 'trade for a living' instead
In reality you can work up your pile pretty rapidly even from a small trading capital base. Do a simple compounding table to $1m.
Then to $1billion; this is where you need to add assistants for the task and use multiple markets where market liquidity issues need to be understood.
Vital requirement: accurate trading methodology.
Add to that requirement a second one: use of a common base methodology for more than one market.