I think Apple considers products to be "vintage" 5 years after Apple has stopped distributing them for 5 years. "Obsolete" after Apple has stopped distributing them for 7 years or longer.
This applies to hardware service and repair parts availability. You might get macOS updates for longer. E.g., a Late 2009 iMac can run anything up to High Sierra. High Sierra came out in September 2017, received a point update (10.13.6) in July 2018, and finally dropped out of "the most recent three" with the release of Big Sur in November 2020. So that particular machine could run a current OS for about 11 years, though with other Mac models, your mileage may vary.
Obtaining service for your Apple product after an expired warranty - Apple Support