By "unlikely" you mean "
mathematically impossible for the founder population to be representative of the H-1B visa holder population" right? Harvard doesn't graduate enough international students each year to maintain this ratio.
With your second sentence, are you trying to argue that about half of H-1B visa holder population went to famous colleges? Otherwise, what's your point?
My point is that the report gives anecdotes and numbers that cannot be used for sound policy decisions.
Anecdotes are nothing new. 100 years ago we would have read how Andrew Carnegie, son of poor Scottish weavers, became one of the wealthiest people in the US through his innovative steel company. While it's a valid point that immigrants can be helpful, it's also a valid point that the US has more than 100,000 citizens - neither point is all that useful. Or do you really think that most of the target audience won't be able to think of dozens of helpful contributions by immigrants, so need a reminder?
Numbers that cannot be used for policy decisions are also not new. I earlier give an example of the report "Most high tech companies are founded by founded by First/2nd gen immigrants", which is another statement that cannot be used to make a policy decision.
So you tell me, based on this report, are immigrants over- or under- represented as (co)founders of $1B+ startups? Should we have different policy changes if they are under-represented, vs. if they are over-represented? Or what if the number of immigrant founders is what we would except from population statistics?
Your views, frequently stated, are pro-immigration. That's fine. I support that, and I speak as an immigrant who is in turn the child of an immigrant.
But this report cannot be used to support your viewpoint other than with the trivial observation that there are ways in which immigrants are helpful.