I think, if there are too many exchangers it will give us many options to trade so that we can get exchangers that have a bigger profit and now there are many new coins popping up so that more exchangers are needed too
You are right that there are many exchanges and many more are coming and now it is difficult to choose one best exchange among many exchanges. However best thing can not hide from us or almost all the traders know about the best exchange that is Binance and then Bittrex etc. Binance help you out in many ways due to its simplicity people find it easy to use it as well as it provides large volume.