> fan-translated versions put more care into preserving intent and readability in translations
There's a reason for this - money. If there's a particularly high quality scanlation, it's because someone has paid a group to do it.
There's a lot of relatively skilled work that goes into translating a manga from Japanese to English: Translation, Proofreading, Redrawing (removing Japanese glyphs and literally re-drawing what they covered), Typesetting, QA. Some of these steps can take minutes per chapter, some take days. And like all skilled labor, they're typically paid. Especially the translators - you can't not pay them if you want both quality and stability.
That payment can take several forms - Patreon accounts direct payments to have a particular manga translated (probably most manga produced will never get an official translation), and tip jars. Many scanlation groups would love to go legit - purchasing the American distribution licenses - but it's a hard road.
Also, the scanlation scene provides something very valuable for the Japanese publishers: free market valuation. It's why the Japanese publishers who hold the English publication rights rarely go after scanlation groups and sites - it tells them which of their properties are worth licensing off to American companies. It's these companies that go after the scanlations, and most groups give in peacefully - often glad for the opportunity to reward bringing manga to their countries.
Ironically, the skilled labor I called out above? It's the same thing that causes poor quality official translations. It requires a lot of labor, lots of time, and probably comparatively small profit margins.