I wonder if that could be incentivized somehow? Or organized, so that the prompting is more systematic and allows to get the PRs assigned more quickly?
Are there things we can do to facilitate the steps PR authors have to follow? Getting a PR merge will always require some level of proactivity, but if we can save them some steps or make them happen more quickly, that will likely help.
Also, often the motivation for an author to do work or reply on a MR is when they post it; it can quickly decrease with time, especially for new contributors - this could be a factor to take into account when trying to get better responses from authors.
Maybe there is a need to accommodate relatively small changes, so they can have a product review without requiring large budgets - otherwise we are missing on small features which don’t go all the way to have product/UX/etc resources? Maybe there could be a light version of the product review for those cases?
These PRs that are stuck, is it because of lack of skills/experience of reviewers for the parts of the code being affected? If nobody feels they have the expertise, nobody feels they can review, then in turn nobody gets stuff merged, so nobody builds experience.
So maybe we could have a kind of roster of core contributors who volunteer to take on MRs in a part of the codebase without good reviewers, giving them explicitly permission to merge code there, since nobody else will review anyway? This way the code can live again - and maybe people contributing to it will in term become maintainers?