2003 - Power Mac G5
2004 - Cinema Displays
2006 - Mac Pro
2008 - iPhone 3G
2009 - iPhone 3GS, MacBook Pro
2010 - iPhone 4
2012 - MacBook Air, Retina MacBook Pro
2013 - Mac Pro, AirPort Time Capsule, AirPort Extreme, MacBook Air
2017 - iMac, MacBook, MacBook Pro, iMac Pro, iPad Pro, HomePod
2019 - Mac Pro, Pro Display XDR
10 of the last 18 have included hardware. I wouldn’t say that’s “rare“ by any means. Even if it was down to 50/50, which it would be if you looked over the last 20, would you say that getting heads in a coin toss is rare? It’s just not uncommon for them to announce Pro hardware when it’s ready, and there have been a plethora of other signs indicating that these MBPs are indeed ready.