There’s no hard and fast rule that says how old a console needs to be for it and it’s games to be considered retro.
There are a lot of people that say that anything from two generations ago is retro. That would put the PlayStation 3, Xbox 360 and the Wii in the retro camp.
Do you think the PS3 generation is retro or if not what consoles do you consider to be retro systems?
I think the HDMI port is a big part of it too. Even if the version of it has changed over time, it’s really simple to plug a PS3 into a brand new TV, or a PS5 into a TV from the PS3’s era.
Technically, you can find all sorts of interesting outlier games with visual settings. If I remember correctly, I think the first 16:9 game was on the Genesis (maybe 32X or CD? Pretty sure it was a soccer game). I know for a fact Pac Man World for the PS1 had a 16:9 mode, and some other PS1 games did. Then on the GameCube and PlayStation you often had to read the manual to find a special button combination to hold during startup to enable higher resolutions or progressive scan. Gran Turismo 4 was one of the few PS4 games that supported 1080i. I never had an Xbox or Dreamcast, but I believe they had better support for higher resolutions. Then the PS3 was mostly 720p, but with some 1080p mixed in. I imagine some of the cheap 2D digital-only games were probably 480p. And then we start seeing dynamic resolutions where things get even more mixed: especially on the Switch. There’s the “4K checkerboarding” that a lot of PS4 games use, and now the different modes that are bridging the gaps with PC’s.