Fun fact, ipv6 was designed to fix this. Everything is multicast and, in theory, a switch could snoop MLD and create a nice map so that "where is the router?" Would send only to routers, and "whose got this up address?" Would send to a small group, usually with only the correct target in it.

However, it's almost always just blasted out to everyone, and every network I've seen that has the mld snooping actually trying to do something just breaks ipv6 in various ways.