This doesn't mean anything, maybe the customers are simply tired of reporting issues. For example last year we didn't do any updates for 6 months because we were afraid it'd break something and we were too busy to be willing to spend the time reporting problems.
We also don't report issues that are already open on gitlab.com, reporting the issue means your customer is willing to spend time reporting, following up and testing your bug. This is your job, not the customer's. At the moment we are only reporting issues that are either blocking us from work or slowing down our development. The majority of issues we are facing are performance problems.
I just wrote a script to plot the number of issues on gitlab-ce over time and percentage of open/close issues, and the overall period they have been open for, you are accumulating issues with: `backend`, `UX`, `technical debt`, `performance`, `CI/CD`, ... labels, a lot of them don't have a Milestone and have been open for a long time.
I am not sure how emailing you would help us, it's not like the problems are not reported or you don't already know about them. It just appears that the priority of GitLab, as a company, is not shipping a quality product anymore.
EDIT: I work in the aerospace industry and one of the stages of our pipelines is to run stress test on our product. I would suggest you to run a stress test on an instance of GitLab, this would be an amazing place to start looking for performance problems.