

The size difference is not significant. This is about the maintenance burden. When you need to change some of the code where CPU architecture specific things happen you always have to consider what to do with the code path or the compiler flags that concern 486 CPUs.
Here is the announcement by the maintainer Ingo Molnar where he lists some of the things he can now remove and stop worrying about: https://lore.kernel.org/lkml/20250425084216.3913608-1-mingo@kernel.org/
For me things actually became easier when I got myself a native Linux install instead of Windows. But I guess it depends on your college.