Wow, in all my 30-some years of life, I never knew that some people called Nintendo's second system a "Sness" or "Snezz" until today.
I am from Northeast U.S., and am in my late 30s. I grew up with SNES in my early teens during the early 90s, prime time for the system. I played it heavily at the time with a lot of my friends. Every single kid and person that i have ever spoken to has always called it either a Super Nintendo, a Super N.E.S., or the less common S.N.E.S. (spelled out). NEVER not once in all my years did I hear it pronounced as Sness, or Snezz or did I ever think to pronounce it that way. When I read the words SNES or NES, I always spell it out... I am having a Berenstein Bears moment here...
I watched about 50 old SNES Commercials on youtube right now just to make sure. It was always mentioned in marketing, commercials, retail, and all official and non-official Nintendo outlets as a Super Nintendo, a Super N.E.S., or Super Nintendo Entertainment System. Super Nintendo and Super N.E.S. were the most common. Nintendo themselves and all 3rd party publishers, have used all three, and NONE have ever said sness or snez. Japanese commercials obviously call it Super Famicom. Can anyone in a non-U.S. country show me any commercials or marketing where they say sness or snezz?
Snezzers have seemed to have magically appeared out of nowhere to me, but i agree with the OP that this is due to the internet uniting the stragglers. Here are my hot takes:
If you say Sness or snezz because you speak a different language in a different country, and sness or snezz is easier for you to say than the initials spelled out, i guess you get a pass.
And I guess young kids who were born after the ess-en-ee-ess era get a pass too, and either don't know any better, or just copy how some idiot youtube streamers say it. If the 1st time you first played a SNES was after the N64 came out (i.e. the same time the internet became popular), yes, you are in this young group.
But if you played the system in the early 90s,and are from an english-speaking country (or even worse from the U.S.), and you call it a fucking sneeze or sness or whatever, you have neither excuse nor shame. (lol) How is it even possible when all marketing ever by Nintendo never said the name that way?? Is it a lazy stupid-sounding nickname you gave it when you were younger, and it just stuck?