One final thought for consideration. I checked the Reaver cave in Blaustein to ninja it 3 times today for its spawn. The first was at like 9 am. The second was at like 1pm. The last was almost 9pm at night. It was freshly cleared the first time i went to check. It was still not even max spawn at 9pm. Things were tweaked waaaaaayyyy down.
You're presuming you're alone here. I had a look at that dungeon and it was hit roughly 10 times today, and most times, its population power was above 80%. Only twice was it at a low spawn. You likely were unlucky.
We're not a MMO, and that's never been our intention. Having others impact your gameplay is part of playing in a shared narrative; your character doesn't exist in a vacuum. Obviously it can be frustrating, something that can be taken in-character, or may be an occasion to pivot to another dungeon instead.
With all due respect the most consistently available content that is enjoyable is PVE content. DM events are not expected to be the norm. There are not really that many AMPCs.
Most high end crafting material is acquired in dungeons. Almost all high end gear comes from dungeons. Its DUNGEONS and dragons. There are more meaningful ways to have others impact your characters story than "I ran that dungeon, this dungeon, this dungeon, and this dungeon 4 hours ago so tough luck no xp for you today." I, and most others, enjoy the more serious moments of RP with high stakes but you cant do that every single scene. Its unfeasible because there are very real limitations on what you can RP without a DM to oversee it. They're volunteers and have lives outside of this, we shouldnt expect them to watch over every scene, its very rare. One of the more active ones was just let go as well, which is unfortunate but the reason was understandable.
A lot of dungeons are also run subsequently because of their close proximity. A lot of the time if people go to say, the library of thoth, they also will clear the trolls and Sobek's temple because the Library of Thoth's exit is right next to it. The fire mines are very close to the Curst keep. Its not uncommon for people to go to several places in Markovia in one trip. For people to hit the ship and reavers and then go to naillat / the brothel. Under the current function of spawn maturation, I do more often than not find myself pivoting to new dungeons. It isnt scintilating RP. Its just inconvenient on an ooc level and spending more time traveling to a new place which also may or may not have been hit within the last few hours.
People hitting specific dungeons on farm probably has more to do with them being over rewarding more than anything else. The fire mines are hit basically every 2-3 hours it feels like since it is relatively easy, only really requires a handful of buffs and ice varnish to clear. The traps arent that hard to get, the locks arent particularly high, and you can get drift metal, dragon scales, blessed antlers, etc. The risk is far lower than the reward. Markovia's treetops in contrast has the potential for many of those same rewards but with a much higher floor of difficulty. The safe in Markovia's treetops has no cheat code like the brothel. It does not have traps either mind you - but the DC on the chest is usually mid 60s into the 70s which does make it much more inherently difficult.
Tejeda is another example of a dungeon that is simply far over rewarding. You can easily get 1/2 to 3/4 of a level with incredibly easy mobs, traps are like dc 35 to disable, the locks are only about DC 40, almost anyone who has a handful of tailored lockpicking / trap disabling gear is able to take care of the locks and traps there. This is one place that was tinkered with a few times, you used to be able to regularly pull 100k worth of loot out of it and now its closer to 50-60k but the difficulty even with a handful of crossbowmen is simply not that high. That is why it is another overly farmed dungeon compared to anything else that a level 8-15 can go to.
Dont get me wrong, I love a lot of the older dungeons and try to go to them. Not everyone does though. They want the fastest and most efficient way to collect gold and items. I cant blame them. Once word gets out something can be found at X dungeon whether its crafting material or a rare drop people who want it will go to that dungeon until they get it. When I heard Cane of Detection dropped in Markovia on my last character I went to several of those dungeons at least once a week looking for it hoping that might be the day RNG smiled on me. It didnt stop me from actively roleplaying until everyone we needed came available. Moving more of the top tiered items out of mid level dungeons would do more to encourage people not farming them than anything else imo. Move the elite tier items to Ghastria, to Sithicus, to Perfidus and people would be less likely to just grind "easy" dungeons for loot.