So why has ET not used something like a Dyson sphere or a starshade to send us light signals as a form of "Hello"? Maybe because by the time a planet is able t

So why has ET not used something like a Dyson sphere or a starshade to send us light signals as a form of "Hello"? Maybe because by the time a planet is able to send such signals, they have discovered better means, faster than light speed, communications. So, the "Hello" communications have been coming to us for maybe millions of years, but like our planet before we understood radio, we can't detect their communications.