In a world where the 'other 99%' have started using bitcoin, but have less money than today's average user and don't use bitcoin as a savings vehicle (let's say price is largely stable so there are better investment opportunities elsewhere) why shouldn't they get together via a grassroots campaign during a global crisis, to move to a client that has a larger money supply ? The argument would be that the bitcoins are unfairly distributed and the rich have too many of them anyway.
You're merging ideas. It doesn't work like that. You don't go from 1% usage suddenly to another 99% usage. That's why bitcoins come into existence over time, all the way to 2033. [1]
There is plenty of time for people at any stage of hearing about bitcoins to get a hold of a good number of them.
Your other point asks why people wouldn't collude to start a different kind of bitcoin, one that suits them better somehow.
Guess what: they can!
That doesn't mean anything to bitcoins.
People currently understand
exactly what bitcoins are, including how many there are, because it's spelled out in the rules of the protocol everyone agrees to by using it. If you change the rules it is no longer the bitcoins the majority of people consider bitcoins.
Anyone is perfectly welcome to change any rules. Bitcoin is open-source. But the challenge is getting enough people to go along with you to have any value.
There currently exist other crypto currencies such as Litecoin. These have been around a long time now and their exchange rate value is still nowhere near bitcoins. This challenge awaits
any other currency. You have to convince people you have a better thing going than the people already convinced about using bitcoins. Good luck with that.
Even if people
say they will go along with whatever new currency you start, if they have bitcoins, say just 1 of them, and that one bitcoin is worth $50K do you think they will get rid of it? Not likely. They will use both currencies to the best of their advantage. For example, even bitcoiners now
hold and use dollars because it works in their interest to do so. In the end people will look out for their own best interests. The new currency exchange rate would NOT start out at $50K per coin. Again, you can't just jump from one thing to another, merging ideas.
Luckily, any value bitcoins do have is
earned value, and not simply government decreed value aka fiat money. That makes them really hard to devalue and/or compete with.
[1]
https://en.bitcoin.it/wiki/File:Total_bitcoins_over_time_graph.png