The H-1B is a specialty occupation visa that spans more occupations than most people are aware.

Most people associate it with IT workers, but many accountants, research scientists, engineers, and other professionals also hold H-1Bs. Where I work, it is the latter categories of professionals that dominate. Many of them have degrees from schools (e.g. MIT, CMU, etc.) much better than schools most of us went to.

And yes, some of them work at startups. They usually start out with an OPT after graduating and then convert to an H-1B.

IT worker and H-1B are not synonymous -- the former is a subset of the latter. It's unfortunate that the latter is used as shorthand for the former, and the two categories are conflated.