The "privacy" provided by so-called private browsing mode is just a smokescreen considering how much device fingerprinting is going on. And widespread surveillance of the Internet backbone not just by intelligence agencies but now private organisations like Team Cymru.
It would be better if we spent the resources on a next generation anonymity network to replace Tor, or some kind of alternative data transport like radio or satellite, which can still be used by small niche communities of free speech activists, for example... A one way data broadcasting system, sending compressed text only, provides near complete anonymity for those receiving it. However as it necessitates buying receiver hardware, it doesn't get very much traction.