I think part of the reason that's it common here is that it's also pretty common for people to just talk forever if they're not interrupted, which can also be i

I think part of the reason that's it common here is that it's also pretty common for people to just talk forever if they're not interrupted, which can also be impolite in certain situations. As chaotic as "anyone can talk as long as they want but anyone can also interrupt whenever they want" can be, it can also balance out sometimes in a way that ends up in a sort of equilibrium.