When they're not thin they're popular (sports, awards), they favor insiders and/or various levels of manipulation (throwing dildos at a match), or both (military strikes, stock market, etc). They're full of natural or artificial drama, and people love to throw money at that.
I have a bot betting on a handful of what I consider (so far) markets that are impossible to cheat (bar UMA shenanigans): nobody has any control over the outcomes, previous knowledge is very limited. It makes some money, but looking at the depth, the volume, and my metrics, even being the fastest 100% of the time without worrying about bankroll, one of them would gimme roughly $1-2k a week.
I have a bot betting on a handful of what I consider (so far) markets that are impossible to cheat (bar UMA shenanigans): nobody has any control over the outcomes, previous knowledge is very limited. It makes some money, but looking at the depth, the volume, and my metrics, even being the fastest 100% of the time without worrying about bankroll, one of them would gimme roughly $1-2k a week.