I currently own a 3DS and a Wii U, planning to get a Switch this year. I also play games on PC occasionally but I really need to upgrade it, and I still have my PS2 though I rarely ever use it.
In the past, I've owned well, lots of stuff. NES, SNES, Mega Drive (Genesis for you US folks), PS1, Xbox 360, GBC, GBA, and... I guess that's it, actually. I don't even know what happened with most of these, I guess I was too young to notice the old consoles getting behind at the time.
by your console history I'd guess you're similar in age to me. i'm not sure what happened to a lot of my past consoles either... i think i gave some of them away to family/friends, while others i sold.
the ps3 i sold in order to buy a wii u... a decision i now regret.
I'm 22, turning 23 in May. I figure it might be more fun if I add context to each of those missing consoles, though.
NES - no idea what happened to it. I wouldn't even know I ever had one if my older brother didn't tell me.
Mega Drive (or Genesis) - pretty sure we never sold it or gave it away, but it has absolutely vanished, which means mom probably threw it away, as moms do.
SNES - someone offered us a GBC in exchange for either our SNES or Mega Drive. As the sensible kid that I was, obviously I wanted to trade in the Mega Drive, but I was a younger brother so when I knew it the decision was already made (sigh).
GBC - eventually my brother traded it for a friend's GBA, because he had nostalgia for the Color.
GBA - disappeared. I'm pretty sure it had always been in my room or so, but it just vanished. Not that it was ever too useful as we never got any proper GBA games, it was a glorified GBC really. Probably thrown away by mom, as moms do.
PS1 - I remember we gave it to our little cousin siblings back in the day (when they were like, really little). It's been years since I heard from it, so yeah, probably thrown away by their mom, as moms do.
Xbox 360 - sold it to my brother's ex (when they weren't exes of course), I'm not sure she still uses it but it definitely exists. The money wasn't much since we split it and my brother's half was a gift to her, but at least my half was enough to get me my first couple of Wii U games (DKCTF and SM3DW), which I really don't regret. X360 was really underwhelming to me.
The PS2 went through quite some times, too, but somehow it survived all these years, I've no idea how. It was broke at some point, then it went missing, then when I found it and plugged it in it just magically started working again, though it broke again after a while, and well... nowadays it's just sitting there. You put a game in it and it works, though I do think it'll begin having a hard time if I were to use it too regularly. It's really great for that highly occasional replay of Shadow of the Colossus, though.