I've noticed this as well. My best guess is either low hardware or just a bad solution.
If they planned to use a unified codebase for Prime app, they likely went with something HTML/CSS-based, which would explain the performance issues. I could be wrong, but it's just a hunch I have.
If there was other apps we use that had the same issue, I'd chalk it up to hardware too, but maybe they simply don't test it on representative hardware? That might explain it.
> they likely went with something HTML/CSS-based, which would explain the performance issues
Not sure, the web browser in the TV seems to handle things just fine, and much faster than Amazon's app, so I don't think HTML/CSS is to blame here. Probably shit architecture/software design, as usual.
> they likely went with something HTML/CSS-based, which would explain the performance issues.
This is the case with a lot of apps that still manage to be performant. So it's quite possible Amazon are writing bad HTML/CSS but that's possible in other languages too.
Indeed, YouTube uses some sort of stripped-down Chromium (Cobalt I think it's called) with the client UI authored in HTML (and friends) for all of their clients and it's not deficient in performance compared to others. The Prime client is notoriously janky, even on Apple TVs, IME.
If they planned to use a unified codebase for Prime app, they likely went with something HTML/CSS-based, which would explain the performance issues. I could be wrong, but it's just a hunch I have.