You have no way of knowing what impact it would have.
However, in doing so you're effectively claiming that WDW would be better off financially without ADRs, since it costs something to maintain the system, but according to you, the restaurants would be filled just as much regardless of how many ADRs are made.
An explosion is not necessary. All that is necessary is any amount of decrease above the cost of maintaining the ADR system.
That we can agree to disagree about.
I'm saying eliminating the practice of booking duplicate ADR's by those who have no intention of using all of them solves a problem for guests, not a problem for Disney.
On the question of impact the imposition of a cc hold would have on the number of ADR's, I go back to your earlier post where you asked "If walk-in demand was as healthy as you suggest then there would be no reason for WDW to incur the expense of an ADR system at all. " Reservation systems are tools for managing SURPLUSES of demand, not for CREATING demand. Did Disney institute Fastpass because seats on Splash Mountain were going empty? Of course not. They instituted it to get as many people out of line as possible. Because you're not spending money when you are standing in line. Fastpass does not create demand any more than ADR's do. ADR's eliminate the need for guests to wait in stand-by for long periods for a table seating, which gets them into other areas of the parks, hopefully near cash registers.