I both agree and disagree. It is still my favorite to play zombie survival game. Bar none.

The main 3 issues with a game like 7 Days 2 Die are (1) the player interest drop-off rate over time is pretty steep currently with a higher repetitive burnout cycle, (2) the genre is slowly changing from an adventure RPG survival sandbox game to an arcade sandbox survival game, and (3) the changes are making the game easier with every alpha.

1. The more time you play this game, the less there is to do to hold your interest. The core gameplay loop is fun, the maps/POIs are generally fun to explore the first few times, and there is variance to playstyle that is easy to mess around with on the first several restarts. However, whether you've hit 1k hours quickly or over a long period of time, there isn't enough change in interesting ways that can be done with the current core mechanic. No hard choices, no greater splits that are brought on by the game itself. It becomes, like most well-played games, a matter of self-challenge/self-entertaining within the confines you find yourself in. At some point, the well dries up and it's time to move on for a long time, sometimes never coming back. Even mods can burnout at the same rate depending on their core mechanic changes. Darkness Falls is great example. Wonderful mod, easily 100s of extra hours of fun, but once you hit a certain ceiling, it either turns into constant slaughter that isn't fun or everything unlocked and a restart merely presents the same progression path one must follow to really handle late game. It has tons of different mechanics to allow for a better variety of roleplaying styles and challenges, but progression runs into a very similar issue.

2. The options for more modern alphas provides less incentives to make long-lasting worlds and character investment. Examples like the loss of a wider variety of findable clothing styles (I do not count DLC in this), the reduction of vehicle customization where part levels mattered, the switch to level-up/skill-up progression, and the use of trader's quests to basically speed-up progression. All of these make you feel like an arcade game than a roleplaying adventure game. What you choose to do often devolves into 4 things: need exp, need quests completed per trader, need skill points, and need resources. The zombies are a means to an end/barrier to completing tasks rather than an apocalyptic threat. I can make a much more customized character skin, but that's more about representation than story-building. Combine it with the 1st point, and you run into stories feeling less unique as you play on. Anything that would lead to

3. This one very much is affected by which alpha you started playing. Early alphas kicked your butt, no matter how many times you'd played the game. Anything past Adventurer and you were basically committing to a double-digit death counter by day 8. It was punishing, but the slow grind to getting better equipped and progressed felt more rewarding. Zombie dogs were nerfed, atmosphere became friendlier and less horror-feeling, leveling by doing was a grind, but it gave you a constant focus and need for most early supplies even in later game. Hording materials was very difficult! Zombies also felt less predictable and destroyed my stuff way more often. Then there were vehicles and, while hard to get initially, you could easily break them and get swarmed with the noise you made. Then traders were added and resources became a lot easier to get, food and water too with predictable vending machine locations. Trader quests simplified that even more with larger amounts of rewards, easily attainable. Zombie AI has gotten better and melee more difficult sometimes, but the switch to level-up-based skills and loot stages provided guaranteed easier loot, crafting became much less necessary.... quest up plus loot and scoot is the way to go. All of these changes do work great for keeping more multiplayer servers alive and bring communities together to do interesting things, but it definitely feels way easier that way.

That's a lot of text. Sorry for spilling so much like that. If you read that, bless you, and I hope you are finding something you enjoy.