Sorting by "last updated" doesn't really tell you anything about the app's quality, and I really do not want to install and try 30 different apps solving the same problem just to see which one is better. Plenty of people have done so before me, so just tell me which one is the most popular!
Mandatory reporting of usage statistics runs contrary to one of the freedoms inherent to FOSS, that the software is for the user's freedom.
But surely there should be a way to reconcile no-spying with usage reporting through some voluntary means. For example, Debian allows users to install the popularity-contest package.
"Mandatory reporting of usage statistics runs contrary to one of the freedoms inherent to FOSS, that the software is for the user's freedom."
Why? You don't need to do tracking, just have a counter on the server that increases every time someone downloads the repository. What does this have to do with FOSS?
I created a small website to display F-Droid apps with their repository information (from github, gitlab, etc), it's not perfect but it can give more insights on a project popularity.
For any given purpose, there's usually maybe three apps in the store that fit the bill. Sorting by last updated is a great way to find the most popular apps, as they're generally also the most well-maintained. There's little reason to keep updating an app when something else does everything better.
The only "old" app I keep using is Barcode Scanner (com.google.zxing.client.android), since it's a classic that will likely never stop working.
Sorting by "last updated" doesn't really tell you anything about the app's quality, and I really do not want to install and try 30 different apps solving the same problem just to see which one is better. Plenty of people have done so before me, so just tell me which one is the most popular!