How long should a Wikipedia article be? Too short, and it won't be informative. Too long, and it will be overwhelming. Finding the proper balance is an enduring challenge. "As long as it needs to be" isn't even the full answer.
If an article becomes excessively long, it may be time to break it up into multiple pages. This measurement is usually made in terms of byte size, i.e. 50 kB might be big enough to split, but 100kB definitely is.
Thinking in bytes, Wikipedia editors must also consider the number of images, which can make an article too "big" for readers with slow Internet connections. And what to include in each article? That's coming in weeks ahead.