> You're correct in that the design hasn't been updated in years, but... so?

I checked a house that was built about 4 years ago in a major metro area, and Project Sunroof just showed an empty field and "sorry, we haven't reached that address yet".

I'm fairly sure nothing about this site is being updated. That also means that any structural changes to houses (including additions, remodeling of the roof, or just complete bulldoze-and-rebuild) or the surrounding property (tree growth, trees being cut down, etc) are not reflected in the estimates.

> Though I wonder if the estimates are now out of date

By all appearances, they are. Massively. The older this data gets, the less useful it becomes. It's not really a "so what?" situation if the data isn't being kept up to date.