Good question.

There was an announcement about QC extending SD 7 and 8 support for up to 8 years but they say it depends on the OEM. Maybe FP is part of that deal. Maybe not.

Now let's look at the Pixel's update support from another angle. The problem I see is that the hardware may not last that long in practice. Specifically due to the lack of parts or the prices for those parts. For example a replacement for my Pixel 8 Pro's battery is currently CAD $160. That used to be $80 when I had a Pixel 5. The screen repair cost is very high. Over the year-and-a-half I've had it, its battery capacity has gone down to 92%. A battery I have almost never fast charged. If this degradation rate continues, it'll need replacement by year 2-3 of the device life. That'll be $160-200 for another 2-3 years. Then there's the parts availability. The Pixel 6a, supported to 2027, has a fire-hazardous battery defect requiring battery replacement. Our extended family has a couple. We checked with the authorized repair shops and it turns out they no longer have those batteries. That's 3 years into the device's support lifespan. This means it's quite plausibe that I won't be able to replace my Pixel 8 Pro's battery next year, let alone in the 6th year of its 7-year support lifespan. In other words that long of an update support is only meaningful if it's supplanted by the necessary availability of parts, and ideally the ability to replace them without specialized tools. I've tried replacing a Pixel battery in the past and I broke a screen. I'm sure I can get the hang of it if I had the requisite hot plates, high end suction cups and a few spare devices to practice, but that's not practical for most users.