What kind of people benefit and what kind of people lose on a bitcoin standard?
Even if you are a successful Bitcoin investor, if you do not use Bitcoin as a payment method, that is, do not rely on it for your financial transactions, you are likely to be a failed Bitcoiner because Bitcoin is a useful technology, not just an investment opportunity.
How would it impact big companies, banks, and governments, and how would adoption speed affect all of that?
All of these entities are primarily profit seekers, so they will focus on profiting from Bitcoin adoption and are not mainly concerned with the technology's spread. We remember how they attacked Bitcoin for a long time, then shifted their stance toward greater adoption as its popularity grew.