Part of it might just be that they have lower expectations for Switch in terms of the CPU being able to keep up with a large megabase. They expect players to be able to launch a rocket without any noticeable lag, but one-rocket-per-minute bases might be a bit much.
Also, they mentioned in the previous blog post that they've done some optimization to keep the framerate from bogging down, so maybe even the x86 requirements are lower these days (or will be when those optimizations show up in the public version, which might not have happened yet).
Also, they mentioned in the previous blog post that they've done some optimization to keep the framerate from bogging down, so maybe even the x86 requirements are lower these days (or will be when those optimizations show up in the public version, which might not have happened yet).