(a) watching movies letterboxed has yet to cause burn in on my OLED and (b) you could make the backdrop a frosted glass version of the same photo...

Not to say that every point is spot-on, but it’s true that Google in general makes their software and UIs complicated enough that outside of perhaps search or betas, they don’t update or change them all that frequently, maybe every two years at best. Apple or Microsoft could by now show them a thing or two on how to iterate user interfaces annually to evolve UI instead of making drastic changes folks might not like or sticking with the status quo forever with rollouts via obscure settings panels.

>Who's to say that your idea is proper

I will fight to death anyone who says different.

>Letterboxing causes burn-in on OLEDs, not exactly ideal for a screen saver.

They letterbox the portrait photos correctly. Well, sort of. They have a small gap between the top/bottom of the TV and the top/bottom of the photo. The letterbox area uses part of the photo so there's no additional risk of burn in. Even if they did just use black, I don't think black can be burned in.