not necessarily. for example there are multiple s and p etfs. SPY used for trading and then each brokerage has their own

It can only go two ways. 
I dont think you are wrong, I think it will also increase over time. 
I dont know exactly which etf will, but eventually one will rule them all. 

Satosora

I do think it will increase. I could be wrong but that's what I think. I think many thought it would happen overnight. Let's see what it looks like in a couple years.