There’s already a recent post about that in the Suggestions forum. Long story short: @Ignasi said that the devs considered that idea and discarded it because it would be taxing on the server.
From that point on, the discussion devolved into speculation about how exactly it might be taxing the servers. Suffice it to say that there are some plausible guesses about why, so we can keep wishing for that system all we want, but we won’t get it 