I think he is referring to development activity. Manjaro has stagnated over the last 5 years or so, there is a lack of innovation, and the leadership does not encourage contributions.
Most core contributors have left, of the sizable group of people actively working on the project 5-10 years ago only 2 remain, and maybe another 2 people picking up small stuff every now and then.
Manjaro ARM is a good example, it is not being maintained actively anymore since ~2023.
There are piles of issue reports being unaddressed, people requesting access to the GitLab which will never be granted, minor issues such as the forum theming having bugs etc…
If a backbone application such as Pamac or Calamaris breaks the project lacks motivated people with the skills to fix it. The Pamac dev has been MIA since the end of last year and there is a reported crash which needs fixing, but it is not getting fixed because there is no backup.