Where did you get the data that investors are not rising? Anyways, its a gamble for exchanges but in the long run they are going to win. Besides competition are very tough in this niche, so its just a matter of time before trading platform cease to exist.
It's a new kind of business that's why many people would like to take this opportunity to form a business in this kind of industry. Some exchanges have very low volume and we can see some exchanges that are taking the attention of millions of people. It's a competition for them to convince people that they should trade in their exchange so they should focus more on having a quality service along with a competitive fee so that they will be considered. It's a good thing for traders to have a lot of options.