Be realistic guys. How can bitcoin stay this cheap if we even get 100 million users worldwide?
To get realistic you should first explain to us how and when (if ever) the Bitcoin user base gets expanded to 100 million users worldwide. The majority of population in developed countries live on credit. It means that they don't save up anything and are tightly tied to fiat and their credit cards. The rest of world population doesn't live on credit simply because they can't get any credit at all (which doesn't mean that they wouldn't if given an opportunity). People in general are spenders, not savers...
The conclusion is that you can safely forget about 100M Bitcoin users for the foreseeable future
Those who live on credit would benefit a lot from crashing the dollar price and buying bitcoin.
Because the less value the dollar has, the cheaper it will be for you to pay of your credit
You obviously totally ignore the other side of the equation. That is, to buy bitcoins, you would still need dollars (which you use to pay back the loan). And forget at that about the simple truth that collapsing dollar will necessarily lead not only to a surge in the Bitcoin price (which should be self-evident) but also to an overall hyperinflation in prices of virtually everything. So, even if they could pay back their loans with cheaper dollars (which is a big question in and of itself), they will still end up poorer (read farther from buying bitcoins)...
In this way, I don't think that buying bitcoins will be an option for all these people