sadly, a nice idea that is painfully naive with how computers are used in reality.
One need only remember how easy it was to take over IRC channels with a few hundred bots to see the endgame of this rationale… it cannot be patched out, it’s inherent to the internet.
That which would make a vote valid; can (and will) be gamed.
It could work depending on how it is set up. Maybe only accounts with n-number of years get 1 single vote, and maybe don't let any random 2-day old account get a vote.
As long as sub forums can be created easily, users may pick their sub forum and thus indirectly moderator.
In this setup having users elect the moderator leads to cases where small groups create their special interest group and then some trolls challenge the moderator.
Their may be some oversight on the large sub forum, but not all.
Necessary for this is that subforums can't have unique names. If a bad mod can squat all the words like "computers", "programming", "coding", newcomers aren't going to know the best subforum is called "RealProgNoBadMod"
You see this in city-focused subreddits. But the reality is the name is power. New users type in their city and join the original one. The hostile mods suppress mention of the new one. It never manages to get critical mass.
A democratic election requires that the elected be your employee, where you work with him on a regular basis to direct him in his job. That works (ish) in government where people doing the hiring have heavily invested life interests in it succeeding.
Does a subforum offer the same? Once the mod is elected, are you going to sit down with him each day to make sure he is doing the job to your wishes and expectations? I say (ish) in government because it often doesn't even work there, even where people have heavily invested life interests, with a lot (maybe even the vast majority!) of people never getting involved in democracy. A subforum? Who cares?
If there were to be elections, it is unlikely they could be anything other than authoritarianly, with the chosen one becoming the ultimate power.
Crucially, SO's election system needs to be bootstrapped: users aren't eligible to vote until they have a history of participation. The level of participation is fairly trivial, but it provides enough signal to allow a reasonable detection (and elimination) of bot / sock puppet networks without resorting to crude measures like blacklists or "bot tests".
For new sites, this meant that the bulk of moderation was done by employees, followed by employee-appointed temporary moderators. This dramatically reduced abuse, but also reduced the explosion of new sub-communities that sites like Reddit thrived on.
It was pretty decent in the mid and late 00s. The community started turning toxic in the very early 10s and by about 2015 was quite poisonous. The saddest part is that the problem was known and spoken about frequently, but the response to that from staff and/or high-level mods was to just double down and dig in.
For sure, advanced difficult topics were never really their forte', although it was really common to get great book or blog recommendations via comments. For me, the golden combination was a good book on the language/framework/topic I was stuyding, supplemented with specific Q&A from Stack Overflow. I have extremely fond memories learning C++ and Qt that way (although that Qt book was a little rough, but at least there was a Qt book. Nowadays every book just seems too outdated to be helpful).
Internet is way behind on democracy. In general everyone likes democracy until they're in charge, then they realise they're the best person to be in charge and the idiots who vote don't have a clue, and should probably be banned if not beheaded for speaking out of turn.
You'd have to weight votes by some kind of participation metric to solve the problem of very little authentication of the voters
One need only remember how easy it was to take over IRC channels with a few hundred bots to see the endgame of this rationale… it cannot be patched out, it’s inherent to the internet.
That which would make a vote valid; can (and will) be gamed.