Guido knew this long before going to DropBox.  Google is still on 2.7.  IIRC I saw some mailing list posts back around 2008 that acknowledged that most large organizations will <i>never</i> upgrade to 3.0, because it just doesn&#x27;t make sense when you have a large legacy codebase.<p>That doesn&#x27;t make Python 3 a failure or unadopted, it&#x27;s just the structure of our industry.  By search &amp; job stats [1], the most popular programming languages are Java, C, C++, C#, and yep, Python.  Companies tend to pick whatever language is best for early adopters when they first get started and then language usage grows along with the company.  So the most popular languages <i>now</i> are the ones that were cutting edge 15 years ago, when the biggest companies of today were tiny startups.  Go look at what&#x27;s most popular among startups today and you&#x27;ll see what&#x27;ll be the hot programming languages in 15 years.<p>[1] <a href="http:&#x2F;&#x2F;www.tiobe.com&#x2F;index.php&#x2F;content&#x2F;paperinfo&#x2F;tpci&#x2F;index.html" rel="nofollow">http:&#x2F;&#x2F;www.tiobe.com&#x2F;index.php&#x2F;content&#x2F;paperinfo&#x2F;tpci&#x2F;index....</a>