> wider selection of extensions, more customizable UI

Nope. Most people don't care about that or in fact prefer Chrome's non-customizable UI.

> and better privacy (separate search bar and URL bar, keystrokes not sent to Google as "partial searches" by default)?

That's what I meant with "Mozilla Foundation's values".

Usually when "supporting a company's values" is given as the primary explanation for choosing one product over another it implies that the customer does not gain or is in fact sacrificing some direct benefit because of a factor that not related to the utility of a product relative to its competition.

Increased privacy is very much a direct benefit for a user and it is a real factor that contributes to the utility of FF.

Which adding DRM detracts from.

You're reading too much between the lines.

That's weird. I know a fairly even proportion of users of each, but people who are power users or close are overall more clustered around firefox, to be fair.