Perhaps so, but this may reflect a lack of power rather than a lack of awareness. I was in a startup once where a new CEO talked about allocation of shares - he referred to the number of shares with no extra context. I asked, in the meeting, how we could calculate our ownership under the exit scenario he described, and clearly there was an uncomfortable vibe in the room after I did that. The disinclination to ask about this may reflect a lack of power rather than cluelessness.
Also, it does need to be stated, many of the employees were H1B workers with green card sponsorship. I'd say that they were behaving rationally by sticking with the company, especially since a couple of them were close to completing the process.
This and many other experiences have convinced me that while I generally look on immigration positively, I believe that workers need to be free and full agents in a labor market (this includes there right to change fields entirely, not just jobs, and it also includes the right to go without a job for a while). I'm convinced that a great part of the appeal of the H1B is that it creates a class of engineers who lack this freedom. Truth is, you don't need all your workers to lack freedom of movement, as long as the percentage is high enough to set a standard.