If you compare Wikimedias spending 5 years ago to what it is now, it has ballooned in such an excessive way if you put it in context. Wikipedia isn't providing double the value of what it was 5 years ago.
Surely it's "worth it" if you want the site to be usable by novice users. This is about optimizing for reach and intellectual diversity, not just "people who are currently adding value".
> Wikipedia isn't providing double the value of what it was 5 years ago.
Wikimedia supports other projects besides Wikipedia itself, and the value it provides has not just doubled but plausibly grown by an order of magnitude compared to its early days. Wikimedia Commons and Wikidata are hugely beneficial to the Internet community, and Wikivoyage is not far behind.
Maybe this wouldn't be the case if pages were less complicated to edit?