Rosetta was first publicly available with Mac OS X "Tiger" 10.4.4, released in on January 10, 2006; the initial release of "Tiger", 10.4, was released nearly a

Rosetta was first publicly available with Mac OS X "Tiger" 10.4.4, released in on January 10, 2006; the initial release of "Tiger", 10.4, was released nearly a year prior on April 29, 2005. Mac OS X "Leopard" 10.5.8 was the last version of Mac OS X that supported booting on PowerPC-based Macs, released August 5, 2009. Apple's final update for the operating system was released in June 2011. An update for Safari and iTunes was released in 2012. Mac OS X "Snow Leopard" 10.6.8 was the last supported version that contained Rosetta, released August 28, 2009. It became unsupported in late 2014, though it received an update in 2016. For all intents and purposes, let's end support in September 2014 with the final iTunes update. So from 2006 to 2014, roughly eight years of official Apple support for versions of Mac OS X containing PowerPC-support. Eight years across three versions. This was before the era of major releases being made available for free every year. If Rosetta 1 was anything to go by, and given that the Rosetta 2 technology is Apple-built, not licenced, we should see Intel support for quite some time — it depends on how quickly software is ported to Apple Silicon, iOS apps are ported to AppKit or Catalyst, and high-speed emulation of an Intel-based release of macOS becomes viable. We may see Intel releases of macOS for a while longer than with the previous transition, given that the most popular Macs are MacBooks, and they run on latest gen Intel processors; compare that to the iBook and PowerBook, stuck on the G4 for years after the G5 came out. But either way, 8 years is nothing to sniff at. :-) Edit: mistook 10.5.8 as the latest Rosetta-supported Mac OS X release; it was actually 10.6.8.