The only thing I can say is games are different. People seem to have a since the games can use a lot of power and be willing to accept that. And you're definitely not wrong, many of them are written terribly and destroy battery life unnecessarily.

But the other thing is it's obvious when I play a game. Where is I don't really think about using Safari, but I'm sure I use it dozens and dozens of times a day. So I'm very conscious of the fact that Pokémon go or whatever else I'm playing eats my battery, but all the little interactions with the web browser eating an extra 20% probably wouldn't raise a flag for me; I'd just think my phone's battery life got a lot worse.

That's my best guess anyway