Bitcoin does not work because people do not trust to buy things with bitcoin. I have a site running now for 5 months selling precious metals, made plenty of sales with credit card, bank transfer, no problems but not a single bitcoin purchase!
What is the point in bitcoin again?
You just answered your questions. Why would a customer that got used to buying with its credit card which works very well for him or her would just decide tomorrow to stop using its credit card and start paying with bitcoins.
Let's not kid ourselves, this will happen very hard. Bitcoin needs to look for its use cases elsewhere. Remittances, banking unbanked and hard reachable zones, etc.. are just some of the possible use cases.
And by the way, we are not ready for these mass payments. At the moment, our blocks are to small and we cannot compete with Visa for example.