I feel the importance of this bullet really depends on the plugin.
Take something large like https://meta.discourse.org/t/topic-list-previews/41630. It’s a large plugin and touches lots of areas of core, thus requiring frequent commits. Compare that with https://github.com/discourse/discourse-plugin-office365-auth. Its last commit was 8 months ago and it works just fine (in fact it’s installed on our business tier).