I'm surprised "private & secure" only goes as far as deleting the browser history and cookies every once in a while. Shouldn't a privacy-by-default experience

I'm surprised "private & secure" only goes as far as deleting the browser history and cookies every once in a while. Shouldn't a privacy-by-default experience get rid of many of the information leaks currently inherent in the web browsing experience? Shouldn't it disable the http referer header and third-party requests to tracking sites? Shouldn't it sandbox flash so that it respects the browser's proxy settings and doesn't persist its own cookie-like objects? Just hardwiring the current porn window behavior into the whole browser seems to create more problems than it solves privacy issues. (Makes search through weighted entries in the browser history impossible, which has 99% replaced bookmarks for me; makes restarting the browser a lot bigger of a deal, especially if it also disables opening recently closed tabs).