Not to nitpick, but when you assert that there are many examples, you should provide at least one example to support your argument. Two examples would be even better, if you were wanting to avoid being accused of presenting the exception as the rule.
I find that I run into this practice all too often. People will use the phrase, "there are many examples of this," without providing any of those examples as corroboration. I've also been running into a lot of people who choose to stress the exception as the rule. It, apparently, is common practice for those seeking to mislead or manipulate facts. Not that I'm accusing you of this. I'm just saying.
As for your point about minimum wage being used to maintain a threshold, or "status quo" as I wrote, I agree. To think that raising the minimum wage would accomplish more than this is naive wishful thinking in my opinion. Of course, it is just my opinion.
It would be hard to level an argument against nitpicking when I could probably be accused of it quite often. In mentioning "historical" examples, I mean that a reasonably knowledgeable person can pick any society and go back in time, and know of a time where there was no minimum wage and simultaneously wealth was concentrated in the hands of a minority class. I left it at that hoping that people would accept historical as the proper emphasis and all the caveats that should go with history would necessary weaken any examples that I could currently come up with.
Plus, I really didn't feel like it was at all essential to my argument, so I left it intentionally weak, not wanting to string off debates on the applicability of early Canada, the early USA, pre-victorian England, pre renaissance European countries, and so forth.
The crux if the argument, without needing examples:
If one could keep the employment rate and the value of the currency constant, raising the minimum wage would indisputably make the minimum wage class richer: they would not be laid off or they would be but get jobs at equal or higher than minimum wage, the buying power of the money would be equal and so they are richer. Thus the dream of using it to empower the minimum wage class depends strongly on one's ability to control two capitalist indicators.
One can also weaken the requirements and still arrive at net gains for the minimum wage class, so long as the net gain from those still employed is higher than the net loss from those who end up seeking welfare due to layoffs, one can argue that it is better is some restricted sense.
In any case, given the reality of economies, doing away with the minimum wage or not increasing it with inflation would be disastrous from a social indicator standpoint.