There is no question Satoshi is a genius, many aspects of his innovation are really remarkable, however Gates (who is very good at the implementation level) correctly spots the biggest issue with Bitcoin: that without a regulated third party it's not fit for trade and hard to integrate it in the existing regulated legal and financial structures. No wonder large adopters like Paypal and Microsoft use Bitcoin in a strictly regulated environment where the third parties can verify who is paying for who. In modern societies where drug traders, money launderers and terrorist organizations pose security risk from the state viewpoint only regulated financial instruments will be allowed by law enforcement, and therefore Gates very correctly states that it seems Bitcoin cannot be such financial instrument. What Gates said (despite what the OP states) nothing to do with privacy, it is all about the ability to comply with regulations.
In the meantime ignorant Bitcoin fanboys state that the lack of regulation what Gates points out is the strength of Bitcoin. In fantasy land yes, but in reality it is not. The reality is that without regulated third parties Bitcoin won't be able to succeed. Only regulated third parties can take Bitcoin to the mainstream ... which completely defies the purpose of the decentralized aspect of Satoshi's great innovation.
The thing is fucked up from wider integration and regulation viewpoint, so it is better we the Bitcoin community and investors listen to smart people like Bill Gates.
Thankfully we had Satoshi to render you irrelevant. Go live your life in your regulated taxed hell, and leave the rest of us enjoy the good things.