> Most programmers have an intuition that duplicating a large software project from scratch, like Linux or Chromium for example, would require incredible amounts of expertise, manpower and time. It's not something that a small team can achieve in a few months. You're limited by talent, not hardware.

But only for the same reasons. Linux runs on very nearly every piece of hardware ever made. The APIs you have to implement in order to run "Linux programs" are large and full of old complexity that exists for compatibility. Chromium is full of code to try to make pages render even though they were designed for Internet Explorer 6.

Conversely, some university programs have students create a basic operating system from scratch. It's definitely something a small team can do as long as you don't care about broad hardware support or compatibility with existing applications. In principle a basic web browser is even simpler.