If it ain't 20 years old yet, it ain't retro.
And 10 years later you say stuff needs to be 30 years old to be retro.
Historically, 10 years was enough age for a system to be considered retro. Heck, some systems could be classified as "Living retro" or retro on launch, such as GameBoy Color that while a powerful handheld, was still a retro system in it's power and graphics compared to what existed otherwise.
We used to call systems that were far less than 20 years old retro, like NES and SNES in 200X where neither were that old, SNES especially which was still getting new games up to early 2000's in Japan. Of course, with this, the times and more rapid evolution in technology than today helped to solidify this. Of course NES looks outright retro compared to PS1 even if there has not been even 10 years yet. Of course PS3 does not feel retro when last PS3 games looked way more comparable to PS5 games than NES did to PS2. And yes, PS3 is old enough now to give NES vs PS2 comparisons. But, if we are honest, Switch 2 as a handheld makes both Vita and 3DS look outright retro, 3DS especially but even Vita is graphically much weaker than it's "PS3 grade" marketing promises.
Overall, if we were honest and not trying to deny our aging and remind us of the fear of that aging and impending death, we 25-35 year old gamers would be honest and ready to say that Vita and 3DS as 14 year old systems have entered retro or fresh retro territory. Both are more than less discontinued and dropped in support though the fact PS3 fans as collateral continued support for Vita PSN game sales is funky. Though, most online games and other online support is long gone with vita, as they are with 3DS.
TL;DR "Who told you 20 years is the requirement for retro? Used to be that 10 years was enough, and if not 15 was more than enough."