Nothing new, How about some data?
— The Macbook Pro non-Retina 13-inch was so popular that it remained in production unchanged from its introduction in June 2012 thought its discontinuance in October 2016. Doing "About this Mac..." always showed "Mid-2012" regardless of when it was actually built. My 2012 Macbook Pro 13" was made in April 2013.
— For a while, iMacs were on a two-year cycle. 2015; 2017; 2019. My 2017 iMac was made in October 2018.
— The last Intel-powered Mini, the Mini 2018, was in production unchanged from Oct 2018 though January 2023. The previous model was in the line four years as well, 2014-2018.
As Kurt says, we aren't talking cars here.
Data source: MacTracker database, free in the Mac App Stores. It would have helped you research this.