That’s true. I should learn enough to build my own containers and so should everyone else. However, Truenas does offer apps just like Synology and QNAP, etc. do and so many may take advantage of that and it is a selling point if I’m looking to get out from under a closed ecosystem.
As you say this the fourth go at apps. That the underlying base layer won’t change yet again making docker out the door and having to convert even custom apps to something different is a possibility. VM’s are at this moment in constant flux too so that is not a safe bet to create a VM to run containers of ones choice in either.
Regardless, it is what it is. Upkeep of apps is hard for the supplier/developer and I think Truenas has found it takes more resources than they would like at this time to devote to it. They did ask for community help in maintaining apps, but I think that requires more intimate knowledge of the apps and time than most people actually have.
I do think they could fairly easily incorporate some kind of changes log for each app that can be either expanded or a link to click on in the app that would show changes. Make it a requirement for apps listed in the catalogue/store to have a change log entry for the update so the maintainer will put something in there.