…and synergy can work to increase value.

The part you may be missing is that once you have the commanding heights, dilution becomes your enemy. Expansion is considered exactly as B1G is doing it.

If throwing out existing members were on the table, you might do this differently. It is bad business to throw out the people who helped build the brand.

This is an expansion process and considering the enhanced value of each new member against the impact of dilution is exactly the right thing to do.