On deletion of answers
There are clear guidelines regarding deletion of answers in the help center that go well beyond "abusive, spam, posted in bad faith, or entirely unrelated to the question", see the page for Why and how are some answers deleted?:
Answers that do not fundamentally answer the question may be removed. This includes answers that are:
- commentary on the question or other answers
- asking another, different
- “thanks!” or “me too!” responses
- exact duplicates of other
- barely more than a link to an external site
- not even a
partial answer to the actual question
This, to me, includes answers to questions that have a clear context in determinate literature and consist of mere argumentation or musings. While answers that only reflect personal musings are to be deleted in general since they are virtually never able to "fundamentally answer a question", argumentations may be fine in some cases as long as there is no specific context given in the question and the argumentation reflects an appropriate knowledge background.
Personally, I would still prefer sourced answers, but a lack of reference can hardly justify deletion if the above criteria are not relevant.
On the deletion of questions
Here, there are likewise clear standards that are much less strict and almost meet the description given in the OP:
Questions that are extremely off topic, or of very low quality, may be removed at the discretion of the community and moderators.
Over time, closed questions that are not useful as signpoints to other questions may also be removed, as well as questions which have no significant activity over a very long period after being asked. If you want to improve a question to keep it from being deleted, click the edit button beneath it. See How to Ask for more tips on improving questions.
Here, at least as far as I am aware of, the second case, i.e. deletion by the community-bot, is much more frequent than actual moderator deletion (as opposed to putting on hold).
Why the uptick?
I guess this is due to a simple fact: We get more flags pointing out problematic posts. This, coupled with the fact that active highrep users that used to handle revision queues are now actually moderators results in very few posts handled by the community by itself. This results indeed in comparatively more posts deleted or closed by moderator votes.
I, personally, would prefer a vivid community of highrep users enacting the StackExchange model as far as their privileges go, but unfortunately, the activity and structure of our community just do not allow for this at the moment.
I agree that as far as escalation is concerned, downvoting surely is the first step, ideally with a comment explaining what is lacking. In bigger and/or more rigorous communities, you can see how this works perfectly. This is just not the case for Philosophy.SE at the moment.
As a moderator, I do distinguish here between posts by new users and posts by the ones that are about for long enough so that they should understand how the site works: The former are given a downvote, a comment and ~24h to make improvements before deletion (if mendable - e.g. comments in answers are deleted directly with a comment as of why). The latter are deleted on the spot.