This is something that the CM team has been thinking about since before I pushed that first set of 29 sites out of beta in 2019. It was, in fact, part of our conversation when we made the decision to do that. One of the things that we've noticed and reiterated nearly every time we've made changes to the Graduation process is that we recognize that there's not one "right" site size and that not every site will be the size of Stack Overflow.
That's no less true today than it was in 2015 when Ana wrote Graduation, site closure, and a clearer outlook on the health of SE sites or I announced those 29 sites leaving beta in 2019 or Rosie announced the round of 59 sites at the end of 2021.
You recognized the same thing that we did, though - we have more and more sites out of beta and some of those sites are even getting site designs… and we asked ourselves… "Where do the 'graduated' or 'full' reputation privileges come in now?" It's not happening when they leave beta… it's not happening when they get a design… so when?
We asked ourselves the same questions you're asking - what metrics would we outline for when we would reach out to a site and say, "Congrats, it's time to have higher reputation levels!" or when a site could come to us and ask "We can haz higher rep levels please?" And the answer that we came to is - if it's not broken, let's not "fix" it. That is to say…
We have no plans to change reputation levels across the board on a site from "beta" to "full" ever. We will only adjust individual reputation levels if the current number is not working.
Now, whether this decision excites you or makes you furious, let's take a minute and work through why we've made this decision.
Site age != big community != lots of rep
When sites moved through the process more quickly, there was often more content being created, more votes being cast and more people with the reputation needed to get the higher reputation levels. But as sites have focused on smaller and more niche subjects with fewer experts to participate and judge content, we realized that those "full" rep levels might never be a good fit, just as getting to 10 questions per day might never be possible. But - that doesn't mean the community isn't sound, healthy, and serving a valid purpose.
Since the last time we gave people higher rep levels, I can only think of one site that's asked for them, maybe two… and I can guess why that is.
Losing privileges is a bummer.
Losing privileges is frustrating to people. I see people complaining about it often - paying for bounties causes them to lose editing privileges or posting an unpopular answer drops them below the reputation needed to see deleted posts or downvoting loses them the privilege to downvote (probably my favorite)... It's just not fun for anyone involved. Heck, it's why we don't take away badges (in most cases) even if you would lose them otherwise.
A bunch of people losing a whole raft of privileges because a subset of users decided it was time to require higher privileges on a site… just doesn't make for great community happiness and can, actually, lead to poorer community engagement. Particularly in cases where there really weren't enough people with the privileges to do tasks that required several participants.
Honestly, I feel like a big part of why we tested 3-vote closure (and it's been so popular on sites) is because many of those big sites with higher rep levels don't have enough people with the close privilege who are interested in participating in that task. Imagine doing that to smaller sites that only have 5-10 active people with 3k reputation. The people who lose the privilege aren't necessarily going to be motivated to earn it back, and may just wander off.
Why are we still using reputation to determine access to privileges anyway?
If you read much of what I post on meta, you may have heard me opine about how we need to stop locking privileges to reputation, anyway. Someone with 100k reputation doesn't necessarily know how to edit a post well but someone with 500 reputation who's had their last 100 suggestions accepted probably does. In a perfect world, we would much rather give access to tools to people who have shown through some method that they know what they're doing - and make sure they continue to perform well at those tasks, lest they lose that privilege.
While we don't have it on our roadmap to start this work, right now we don't think it makes sense to further push the rhetoric of reputation being equivalent to ability on these sites by making people re-earn privileges they've already shown they're more than capable of using well.
Our site has an influx of crappy tags from low-rep users… we need higher privilege levels!
Whether it's tags or close votes or post deletion, this is where the second half of the big bold header up top comes in. "We will only adjust individual reputation levels if the current number is not working." So, the narrative here isn't "you're just going to have to deal"; it's - "OK, tell us about the problem you're facing". If your site has newer users going on tag creation sprees or voting to leave open questions that should be closed, that's bad! Let's see what we can do about it - and this includes cases where the "full" privilege levels may be too high.
Whatever the privilege, we can adjust it on a per-site basis without changing the entire site to the full site privilege levels. This is why Stack Overflow has even higher levels for some things - including tag creation. We want to target the specific problem your community is facing rather than having potentially negative impacts on all privileges because of an issue with one or two.
While I can't say we'll never change sites from beta to full rep levels in the future, sites should be aware that it's unlikely we will. If closing and reopening are working fine at 500, what's the purpose of flipping it to 3k? If there is an issue, we can address it; otherwise, let people do their thing!
For a full listing of the privileges and exceptions, check out What are the reputation requirements for privileges on sites, and how do they differ per site?