I partially agree, in the sense that playstyle has a huge effect on these things, but this has been an issue for a long time with some huge supporters of the game (the ones that immediately spring to mind are Mr Atomic Duck and Zed Survivor, but there are plenty of others that I can't recall right now) bringing it up as a Thing to Sort Out. It also feels like low-hanging dev fruit. All they really need to do is implement something like the Wandering Zombies and/or Horde Night mods into vanilla and the problem largely ends. And before anyone says "just install those mods then!", it is not the responsibility of modders to solve the game's biggest known problem (late-game boredom). That's got to be on the devs, with modders adding cream on the top of the cake.

I think zombies thumping fences is broken for a gameplay perspective.   I start my games in Muldraugh gated community on high zombie population.  What I do at the start of the game is start an ambulance siren at the front of my house if one spawns and then I start shooting my pistol. I have basements at always so I sometimes find a shotgun and some ammo too and I use that too. When the helicopter comes I just stand at my house and blast away.   The problem is that the zombies come along the fences towards fighting, shooting, sirens, helicopter and at a certain distance from the player they just start thumping on the fence. I have never had them break a single fence even after killing 400-500 around my house. They just line up along the fence and I get 100% stress and then depression in 1 second. As long as you do not move away from the zombies to a distance where they stop thumping and then make a new noise they never come in enough numbers. They just stop.   When you get 75% endurance you just sit down and fast forward. Fast forwarding seems to break zombie pathing towards sound or players. The endurance thing also leads to a much safer play style. Every 5-10 zombies you retreat out of danger, sit with your back to zombies, fast forward and go in again. You never get surrounded. You only scratch the surface of a horde and then clear your exit route when going to rest or when returning to the slaughter. There is no point fighting yourself into a dangerous situation because you can not fight. You encounter a few then 3 more drip in and you are done. Rest, Repeat and the horde is gone.

Early access alpha since 2011, I don't think they can reasonably expect people to pay for DLC. The game has been out for so long that everybody has heard about it and those who would have bought it have already done so. They would need to make something very compelling and polished to get new eyes on the project. If you are in a situation where it takes you 3-5 years multiple times to bungle through layers upon layers of intermingled spaghetti code and deliver what has been delivered then I do not think PZ is financially viable going forward. At some point the world moves on. People finish school, get a job, get married, have children, their children start schoo,l etc.   It is a fun game but being in early access for 15 years is beyond a meme. They need to concentrate on their next thing.

We will look into this in the next update as a bug, it seems to be an issue specific to the GoG installer as I cannot find any similar mentions of this in Steam.

It's not a problem of money. They choose to keep theirs teams small and they need to deal with technical debt, while upgrading their game engine. But they keep multiple astronomical goals almost impossible to deliver. It's a formula for disaster and TheIndiesStone is not the first studio to have choose it.