Yes, this is a huge problem. I think NPC's will fix everything though because this is early access no wonder it has major issues. Something like a post-apocalyptic nation management game might be the endgame. I'd like that.
As you said you're not supposed to survive a very long time in PZ, that's why if you do you should make a new game but harder. Make it so hard that each day passed is an accomplishment
PZ is a game about challenge, if you survive easily for months then you're not playing it how it is intended, at least that's how I see it.
In the settings I'm playing with right now there is no endgame, or there is one but I'm not good enough to achieve it. (sandbox preset down there) Zombies are so powerful, so many and the conditions so hard you can't even feel bored for one second. You constantly need to get rid off zombies, make your safehouse stronger, find food etc I even almost died of thirst because I couldn't get next to a building or a river to get water after leaving the area where I was established, because it was ovetaken by zombies. I had to live in this cabin for some days to recover from the last attack.
But yeah I understand that some people would find that more frustrating than fun and would want other objectives than just survive
Edit: I also attach to my comment my modified spawnpoints.lua file for Wespoint and fireofficer, to have the best experience of it, if it interests someone. It spawns you in some houses of the south east corner of the map