Veteran technology reporter and columnist Om Malik writes: Pitchbook, a data research company has come up with a list of top 14 most valuable startups in the United States. There are no real surprises -- they are all ranked by valuation and they all are valued at north of $4 billion. They are all household names -- barring Outcome Health and Samumed. And they have been around forever. They have thousands of employees and many have billions in revenue. What they are not is liquid on public markets. They have not IPO'd. In a different Silicon Valley, they will all be public companies and they won't be deemed startups. Revenue, growth, relative size, market share -- pick a metric (except for lack of profits in many cases) and you know they aren't really startups. So can we stop calling them startups -- and instead maybe call them VC-backed private companies -- otherwise the label startup loses its meaning.