Professional traders do not need 20,000 screens. Think about it. What do you think is the relationship between number of screens and $$$? There are three possibilities:
Diminishing Returns
The first one is silly, eventually, you get to a point where you can't pay attention to all of those screens. The benefit to you diminishes at one point or another.
The second one is even sillier. If it were exponential, then every hedge fund and investment firm would be buying screens until the money stopped coming in! Every new screen would bring in even MORE profits.
The third one makes the most sense. That more than 3 screens, you start to become distracted…