Everything needs time to develop and nothing remains same in crypto system, it is natural to have so many exchanges because all projects want to provide unique service(better quality, easier trade, more options and profit for users)that will be user friendly and adapted in most countries. For sure we will still use top ones, but if one day you discover you have so many opportunities on other dex-why not try?Every next exchange is a better version of the common used).Look to OAX and LCS for example).
I agree that nothing remains the same in crypto system.Just imagine seeing a lot of exchanges offering trademarks to users with benefit of them. Because of these competitions of exchanges, they are going be develop just to be chosen because of what they offer to users. But surely those top exchanges are what we are going to use considering that they provide unique services that would meet our satisfaction.