Bethesda took a game that could be fun for a week and tried to use mechanics to stretch it into something that could be fun for 2-3 months, giving them enough time to add more content to the game. They failed. Fallout Shelter, despite never asking you to spend money, basically just gets worse the more you play it because you're constantly being badgered by intentionally annoying "speed bump" mechanics and other artificial barriers.

Bethesda took a game that could be fun for a week and tried to use mechanics to stretch it into something that could be fun for 2-3 months, giving them enough time to add more content to the game. They failed. Fallout Shelter, despite never asking you to spend money, basically just gets worse the more you play it because you're constantly being badgered by intentionally annoying "speed bump" mechanics and other artificial barriers.