The title is about "welcoming" but most of the text is about "reputation" (including "sympathy upvotes").
It seems to me that the site's Moderation policies for Questions is the site really going out of its way to be unusually welcome or non-hostile towards new users, I'm not sure what more is feasible without the site's losing its character completely (and becoming a forum or a chat site instead of a Q&A site).
I also think that there is a good case to be made based on the data available that some users likely see reputation as a competition and stop upvoting content worthy of an upvote if they don't want a user to get much reputation.
I like to upvote -- though perhaps I've become less enthusiastic recently, so thanks for the reminder that voting can matter -- and I can see from here that so do (or so did) most other high-reputation users.
People can vote as they like, personally I try to upvote if there's something good about an answer and nothing "bad" i.e. nothing I disagree with -- if there's anything I disagree with then I tend not to upvote, I imagine that's why you'll sometimes "see" me not upvoting something.
I wonder sometimes if I should award "bounty" (to give/share my reputation to others) but I fear that would be putting undue attention on reputation, and risks playing favourites, and just make the problem worse, so I haven't done that.
There's a Christian aphorism that "love of money is the root of all evil", you might say something similar about love of reputation. I think of it as a measure of how much you've used (posted on) the site, which is a metric that's mostly useful for assigning privileges e.g. whether you've used the site enough to know what the site's/community's conventions are (especially about what topics should or shouldn't be closed).
I think the important threshold is 500 or 750, that's where you can be considered a "high reputation" user.
If it's above 1,000 then you're an "old friend" IMO.
Which results in average answer/reputation score decreasing over the course of one's participation even if the content's quality is maintained or improved.
I think it's that there are fewer avid users than there were a few years ago -- there are fewer people on Meta too.
Furthermore it seems to me that too many questions by new users are getting locked without much effort to mend the content and resolving it otherwise.
IMO there are few closed questions, less than one a week which is almost none.
Plus I see an average of about two deleted questions per week, mostly not closed and (from a quick sample inspection) mostly self-deleted i.e. deleted by the post's own author.
Thus willing contributors are quitting because this place is straight up passively or otherwise aggressive and discouraging.
That may be a problem -- and "the place" being "aggressive" might be an action item for moderators (as you know).
There have always been a few questions on meta about how to make the site better and/or more popular.
I personally think moderators are doing an awful job at encouraging participation
You're welcome. :-)
and seeing their own limitations in expertise
I did ask other people when they were volunteering me for the job, but they declined and so here I am.
Not a great job but somebody has to do it.
It might be hard for me to get the right balance, here you're saying that moderation is too aggressive, in other contexts e.g. here you have reckoned I am too permissive, too laissez-faire.
what do you expect from a perfectly enlightened householder
I try not to expect too much, isn't that right?
I think Andrei's reputation comes from posting good answers (mine is more due to having posted many answers).
IMO it's the users of the site that are important, it's the content that's worthwhile (or not) -- the moderation and the meta and so on is a bit of a chore.
Apparently (given what I've read here on Meta) every moderator acquired at least one "hater" who at least for a time seemed to despise or vehemently disagree with them -- and apparently (given what I've read of moderators of other sites) fwiw that's a bit the experience of every SE moderator but what can you do.
The Code of Conduct recommends that we "Focus on the content, not the person." Maybe it's better to focus on specific site policies and how they're applied to specific posts, instead of on "Him" -- "He abused me, he struck me, he overpowered me, he robbed me." and so on!