How is a market with many participants not ideal? It seems to me the messaging "fragmentation" is just the free market actually working and people being willing

How is a market with many participants not ideal? It seems to me the messaging "fragmentation" is just the free market actually working and people being willing and able to choose something other than the defaults and it working out. There's stuff like Beeper that allows for consolidation of multiple services, if you don't like having to use multiple apps for different people.