The Nintendo Switch on a chipset that was outdated a decade ago can run Tears of the Kingdom. It's not sensible that modern hardware is anything less than instant.
Nintendo comes up with a working game first and then adds the story - BotW/TotK are post-apocalyptic so they don't have to show you too many people on screen at once.
The other way you can tell this is that both games have the same story even though one is a sequel! Like Ganon takes over the castle/Hyrule and then Link defeats him, but then they go into the basement and somehow Ganon is there again and does the exact same thing again? Makes no sense.
Should I draw from this conclusion that modern software is not designed to run on modern hardware?
Nintendo can do it because they only have one hardware target (unlike multiplatform games) and they can spend an extra year or two doing performance work.