Yes, there have been some profitable projects. But there is no doubt the number of failed projects is much bigger. Any way, no one force people to invest in a project. So no one should complain.
There are success and failures in investment.
Investment can call as a gambling also. you should be aware on the project you will invest with.
You must have the knowledge and did research before putting any amount on this.
As a real investors you are looking for a long term as the project must be done first.