Manpower issues is just a nice way of saying that we have lost a lot of people since 2014 and we are unable to provide what was once routine and normal for foss communities.
No it is not. Just the available manpower is now otherwise bound (if actually ever it was where you say).
This may either be fluctuation. People come and go for many reasons. But for those gone others came, so that is normal.
Or it may be that a person moved their area of interest. Also happens everywhere.
Also what the hell to you define as "official support"?
There are no dedicated support workers of any kind. And never have been.
Support has always been voluntary. And for the most part by members of the community, rather than by those from the "teams". Simple because the amount of people in the community is magnitudes bigger than the size of the teams.
And that has worked well in the past, and for all I can say still works well. But it has, does, and always will mean, that those asking for support will have to do it in the way that those providing it have chosen.
And that is the way (afaik) that it is in any FOSS project (with the exceptions of those having commercial backing).
Maybe the community has changed. Well most likely. Everything changes over time.
And as for the "real time": Chat and Forum are both as able to be real-time as the other.
If someone wanted to answer to forum message immediately, they can use email notify or other means to be aware of incoming posts. And all else is a matter of how quick they can type. But typing into the forum is not slower than the same in a chat.
But in both instances, its down to people having time to stare at their screen waiting for something to respond too. If people have better to do... Well then you get chats were people may be logged in, but take 5, 10 or 15 minutes before they reply.
But anyway. Point is, that is in no way a consequence of what the project itself does. The project does not (nor ever has) dictated to the community how the community should or may interact.
The project may supply this forum, but that is one out of a great many forums for the project. The majority of the means to interact comes from the community.
And again, that has been this very way for a long long time.
So this is what the community does for the project and maybe today it can do more by the means it uses today.
Chat may (or may not / I have no data) once been more popular.... Well so have light themes for the IDE once been more popular (when CRT screens had just gone), and floating windows too (instead of docked). But those things change.
That change does not mean that the quantity or quality of the community decreases. Not at all.