I can understand the PS360 argument. It was probably the last generation where most games were actually playable off the disc without a bunch of patches.
With how common DLC and stuff was becoming that generation, though, I feel like it’s sort of a soft boundary for retro. I can equally accept retro being anything before the PS360, or before/including that generation.
I don’t look forward to the days where “retro gaming” refers to “any console with physical releases at all”.