There's a lot of comparisons between Wikipedia and OpenStreetMap, and I think this one is valid: when Wikipedia first started out, its mission was to populate new articles. As most topics became fleshed out, they transitioned to having higher editorial standards (ignoring the various dramas for now) and spending more time curating existing articles.

OpenStreetMap is in that 'early' phase: tons of edits are adding new data for fundamental things: streets, houses, addresses, land uses. And it has a barrier to entry - you have to be a tiny bit nerdy to confidently make edits. But in the not-so-distant future, it will need to transition to more and more maintenance and data quality tasks.

Personally, I think a good intermediate step will be to embed better and more automated review processes. The simplest one is in use by companies/agencies that use the data already:

1. Take a snapshot of your region. Vet it for your use case and deploy.

2. Grab a new snapshot at a later date (time to update the service). Look at the changes - is anything wrong or popping out at you? If so, fix it, then download + deploy.

If this becomes the primary means of adding data to OSM, a similar two-step process could be embedded into the contribution mode: Add data, then get the edit reviewed. Plus, there are automated tools to spot and characterize changes already (e.g. QA tiles) and they'll only get better.