Well, it takes my survivors 4 hours to return from mission. I have 10 survivors and i send them out in groups of 2-3, depending on theyr speciality. 4 missions, 20 mins, bit more time on recycling/upgrading and then to help others. That takes me around an hour. Rest of the time i watch some movies or play something else. Havent spent any money on the game and dont see the need either. I found the 1st can of fuel after a week of playing or so, if not counting the ones in the trash piles around the compound.
Btw, maybe u havent thought about it but keeping the site up takes money, server rent/maintnance, ppl wanna get payd for theyr work and without the cash players your wouldnt be playing most mmo/mmorpg-s for free.
And if u'd see a chance to earn bit cash would you say no to it? Anyway, everyone is entitled to theyr oppinion. I've played games like these before and i like them. Spend like 30 min in game and then go have fun with friends or play something else. No1 is forcing u to play btw :)