Normally, investors want startups to either exit or go public. They're not exactly interested in making some small return before.

They want to make at least 10x the amount they invested, that's why it's worth it for them, even with the risk of losing the capital (and that's what happens to a considerable number of investments they do).

This is specific to the location and the opportunity. Suppose if you are in India and you invest in China, then you may expect a return of 12-15% however the same may reduce in US. Now, depending upon the opportunity, the same could go as high as 10x p.a.