Why just millenials? I'm GenX and it breaks down to this:

1) You call. This means that either (a) you know me and want to talk (b) you don't know me and are calling from a business.

2A) I know your number. This means that either (a1) I have time to talk and will (b1) I don't have time and we both know that you can text me with anything important.

2B) I don't know your number. This means that either (a2) you are soliciting business and there are eleventy-seven better ways a more savvy vendor can get ahold of me so fuck off (b2) you are a production company gearing up for a new show and want to get ahold of me via phone 'cuz it's much quicker.

So the only reason for you to leave a voicemail is if you're about to contract with me for thousands of dollars of work. And if you're in a hurry you're going to email me anyway because the person who gave you my info gave you my vCard and you've got no less than five emails to hit me at. And even then, I'm hired by text about as often as I'm hired by voicemail.

Well, that or you're my mother or my mother-in-law. Who leave "it's just me" voicemails because they're in their 70s. But shit. Even my father-in-law texts if he's got something important.