[lumost]

the two largest employers are both the number one players in their market, being the number 1 player in a market may require that you invest for "first mover advantage". This would lead to a lot of failed/re-tooled initiatives over time.

Being number 2 often just means copying the number 1 player in a more capital efficient manner, product descriptions become "X did it this way, customers want it this way". In a winner takes all market, being the first mover matters a lot.

[toyg]

Also, diminishing returns. In many markets you can "get to the table" with a small crew, but to actually win the customer you'll need bodies almost entirely dedicated to it. And it's that sort of margin, multiplied over and over, that makes one company the undisputed n.1.