A lot of investors have such experience. Such experience helps to understand the market better. But because of this many investors do not trust any ICO at all.
And I think that investors will not soon be investing again in new projects as much money as before. Now we need guarantees.
There can be no guarantees. This is currently a startup industry. Not all projects can survive. Even if there were no scam projects, more than half of the failed projects could be.
The same situation is offline. A lot of startups offline can not servive becase of competion and bad market conditions.