Exchanges are like digital banks? This is where you are wrong. No way exchanges can be compared with banks. You can say people use it as "digital banks" which is in fact the most irresponsible thing a person can do. Exchanges should never be used as a place to store your coins. Exchanges are prone to hacks no matter how secure they claim they are. Remember, nothing in this world is 100% perfect or secure. Everything has flaws.
They will eventually reduce fees and profit margins as more competition arises. But do know that, even exchanges has to earn money, so don't be expecting extremely reduced fee from them.