Because it doesn’t seem to matter currently if you play ranked games or casual games, the general experience tends to be the same. But one has numbers and things to go with it. You still get people playing to win in casual games and you get people dicking around having fun in ranked games, and the ranks don’t necessarily indicate how they play as a team and a whole bunch of other things that make it less than ideal.
There was a brief time in the late 90s to early 2000s where you’d just hop into an open server. The lobby would keep the same players as it went round to round and people would just filter in and out as they felt like it. It didn’t track scores or stats between games, and there wasn’t a leveling or progression system that followed you. You just played through the round as it came. People seemed to care a whole lot less about their record or team–it just seemed like everyone was happy to be able to play online. Maybe it’s just because I’m older now and I’m looking back at it with rose tinted glasses, but I wish we could go back to casual modes like that. I don’t have the energy or will to deal with people the way it’s set up now.