That 2009 announcement makes several very specific promises which conflict with these results. It promised signed-out customization based on prior search histor

That 2009 announcement makes several very specific promises which conflict with these results. It promised signed-out customization based on prior search history (which Google has confirmed Incognito doesn't use), with a notification and option to disable that customization. This result finds substantial variance with no notification and no toggle, which extends almost unchanged into Incognito. I think Occam's Razor says this is about localization and device type than fingerprinting, but it's definitely not just the thing they announced in 2009.