some extra light on this:
so with Space Exploration we have a startup setting which hides the Quality mod for when you accidentally load with it and experience the WIP compatibility, the setting acts as an opt-in with a warning that stuff can chance in between versions and to not cry if things break.
as part of this the quality items, prototypes & technologies are hidden.
one of the other "issues" of this category is that alt-scrolling still allowed you to go through all the qualities, we "remedied" that by having a consuming custom input for quality cycle up and down, in favor of setting the next of each quality to nil since that "breaks" existing stuff in the world.
for this and
132877 i had to unfortunately resort to a hotfix that "breaks" existing stuff by removing the quality unlock effects from the technologies so only ever normal is researched in those circumstances, which is not a solution i am entirely happy with but it is the least worst one.
making normal unable to be hidden when quality is enabled sounds good at first, but it'll likely mean the quality diamonds will just have normal in there compared to just only showing a tooltip line, that would not be preferable visually, and the quality diamonds are controlled via the feature flag so there would be no way to hide those if normal quality is forced to stay hidden in that case.
the cleanest method would probably to chance shouldShowQualityGui and have a hasMoreThanOneVisibleQualityUnlocked instead of hasMoreThanOneQualityUnlocked, but that is just as an outside observer, i am not aware of what side effects changing that might have.