What exactly do you expect of companies that go public? What you wrote, and seemingly reflective of a common sentiment, is an extremely loaded statement of what anyone should expect of "glorious publicly traded unicorns".
Unless Twitter committed fraud by not disclosing something, then there should no really no other expectation or aberration in their publicly traded status. The banks, board and the CFO priced the shares and they've been printing money for all their employees using the deep liquid market that all these people fawning over tech companies perpetuate.
So I'm a little confused at what is so interesting about their poor performance. Have you seen the stock market, some companies' shares go up, others go down.