For me, it's hard to see the Playstation as a retro console. I still remember when it was brand new.
That's exactly how I feel about the PS2. I feel kinda weird seeing people call it a retro console.
But, the PS2 is now 12 years old. The way I see it, is if the system no longer being made and games are no longer coming out for it. It's no longer a "modern" console. So if it's no longer a "modern" console, wouldn't it then become a "retro" console?
I think it's just where people think the system is still TOO modern to be called a "retro" system yet. Give it at least 5 more years and then probably it'll be more "retro" then.
My list would have to be:
PS1
SNES
Game Boy (original)