The reality is that the Big 4 aren't all that Big. They are very rarely in the top flight at the same time.
Since the war top flight seasons
WBA 49/50 to 72/73, 76/77 to 85/86, 02/03, 04/05 to 05/06, 08/09 to 17/18
Villa 46/47 to 58/59 61/62 to 66/67 75/76 to 86/87 88/89 to 15/16
Blues 48/49 to 49/50, 55/56 to 64/65, 72/73 to 78/79 80/81 to 83/84, 85/86, 02/03 to 05/06, 07/08 09/10 to 10/11.
Wolves 46/47 to 64/65, 67/68 to 75/76, 77/78 to 81/82, 83/84, 03/04, 09/10 to 11/12, 18/19
In the Premier League there have been just 2 seasons when all four were in it and let's face it Wolves Blues and Ourselves have spent extended periods of time outside the top flight. Even that massively big huge club Aston Villa had the better part of a decade cooling their heels in the 2nd tier or lower.
The region does not seem able to sustain 4 top teir teams simultaneously. It is Villa's and Wolves time now and well nothing seems to last forever. I am sure they will find new and inventive ways of screwing things up.