I do feel that its not worthy if investors are not rising as well !!
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.
How many exchanges do we have right now? 200 or maybe 300? And how many traders do we have? couple of millions? So trading platform is not saturated and a lot of room to grow.