Streamers, media, and Friends & Family make up less than 10% of the invites overall once all invite waves are accounted for. The rest go to random people who sign up.
The issue is, millions of people sign up so chances of YOU getting in, are still low.
I have never streamed and have no social media so 
I still get in though.
Vanilla WoW. I got into beta back then and have been invited to every beta since.
This is such a random question. Do we really expect the average forum-goer to shoot for beta let alone get into it?
MoP d/t the sub shenanigans. Been in every beta since.
First Alpha invite was Vanilla, but first Beta invite was TBC.
Cataclysm.
I believe WoD was my first but i didnât want to mess with it and get any spoilers. Although, it didnât really matter anyways.
It was Mists but I didnât realize I was sent one until after it launched
I got in BC beta as my first. Iâve been in beta for every expansion, just not vanilla.
Been in every beta since WOTLK
Not a streamer, employee, or otherwise, and Iâve had Beta if not Alpha for all but maybe 3 versions of this game. I donât think your numbers are accurateâŚ
Vanilla but donât recall how I got it.
i believe it was MOP. i saw my keybinds werent mapped, so i logged off .
have never been invited, probably never will.
i get it, my account has been silenced and ive been banned from the forums because i do not sugar coat my opinions.
also, beta has been used for a glorified advertisement campaign anyways. the game launches with hundreds of game breaking bugs every time. so itâs not a huge loss on my end.
Iâve been invited to all except TBC, so Iâve been pretty lucky. 
I signed up for Dragonflight Beta so weâll see if the luck continues. 
Beta sucks, Blizzard uses it to find dark patterns to torture us with and get early feedback for things to double down against.