We'll likely have a mostly cashless society, but that doesn't mean anything for Bitcoin. Digital cash denominated in US dollars will rule the US economy, as it currently does, and Bitcoin will not meaningfully penetrate into day-to-day commerce or business transactions. Compared to digital cash, Bitcoin is clunky, slow, and needlessly complicated. Centralization is not nearly the problem Bitcoin proponents want to make it out to be. Everyone hates PayPal, but PayPal works exceedingly well and Bitcoin really can't touch it because most people want a centralized authority they can trust manning transactions in case the other party commits fraud or acts illegally. A trustworthy central authority (the payment middleman, like PayPal, MC, Visa, etc.) is far superior to a decentralized system where payments can't be reversed in cases of fraud.
The centralization of Bitcoin may seem at first like a threat to its existence, but it's probably the only way to effectively accomplish the things that you mention. Bitcoin doesn't really have the ability to be widely used as a currency at this stage like you said, but it has features of anonymity and tax evasion that will continue to attract people to use it. I can't exactly see it being widely used for day to day transactions, however.
Cash will still reign I think because it is what makes things get done. You can get better prices, faster service, more favorable conditions with most vendors if you pay in cash. Digital money is still clumsy as well in my opinion.