While I'm not gonna say the former can't succeed ever, the latter definitely will give you a better edge compared to the former. Pretty much because you'd be able to cater to a wide variety of gamblers—at the end of the day, everyone will have their own preferences.

As for me, while I do like playing slots the most, sometimes I get bored or annoyed lol, so I check out other kind of games. Honestly speaking, I think a lot of people's attention span are getting shorter over time as well—maybe because of social media centric environment— so it'd be nice to have a huge game library to tap.