I, personally, gave up trying to update the data for my area, because about once a month all changes get reverted as "they may be from a copyrighted source" (which happens to be the public domain federal mapping service).
Someone else was more persistent, and managed to get my suburb as existing after five years.
There's a lot more to it than just nobody having volunteered to do the legwork yet.
You cannot just copy and paste things from a public domain data source without first checking the copyright terms and making sure that they're compatible with the OSM license (if they are, you can comment on the revert changeset saying so):
In my experience, the satellite imagery available in the OSM editor to trace buildings and paths (which the other commenter was talking about) - and when I want to add shops and other things; a quick survey with some photos - are both more than enough for most things.
> You cannot just copy and paste things from a public domain data source without first checking the copyright terms
There's an oxymoron here. Many public data sources that are free to use, do in fact have copyright considerations to be made, correct.
However, "public domain" does not have copyright terms attached. That is why it is in the public domain. If something is actually public domain, there is no copyright holder, and no terms to be enforced.
If you do find an area with missing data, do feel free to create an account and add it yourself.
That's literally the only way the open source map gets better.