As if planets were still a necessity for advanced enough civilization once they get their megascale engineering going to fix all their resource and energy probl

As if planets were still a necessity for advanced enough civilization once they get their megascale engineering going to fix all their resource and energy problems. IMHO that's how we will detect the aliens, by spotting one of their megastructures or their side effects (waste heat, gravitational effects, light blocking, stray directional coms traffic, etc.), not by getting any targeted message handed to us on a platter. Could be we are seeing some of that now, thinking it's a some kind of a weird but natural phenomenon.