Is the Python 2->3 process and decisions surrounding it an important part of Guido van Rossum's long career? Sure. Does the fact that Dropbox, quite predictably and like all businesses with large Python codebases has also had to deal with that transition add anything interesting, unexpected, "curiosity-gratifying" to a story about his retirement? I'm not seeing it. It's a long thread of stridently off-topic comments most of which aren't even about Python, never mind the dude's retirement.

Business decisions. Dropbox needs to stay competitive especially with all the alternatives from FA(N)AG (removing Netflix). Many alternatives come bundled with other services.

Not all companies have the big tech or mid/early stage VC money to throw around. Who knows what kind of other tech debt Dropbox has accumulated.

The article doesn't say "only now".

It says "He has already put into motion the conversion of the Dropbox server code from Python 2 to Python 3. "

"already" refers to "sometime in the past 6 years".

Motion describes something that isn’t stopped, meaning not yet complete. This implies it’s more recent, or the conversion is more difficult than it should be.

Perhaps it’s already done, in which case this word choice is poor.

There was a blog article maybe a year ago, that Dropbox finished migrating client side code to Python 3.

He also spent large amount of time working on mypy (type checker) which my understanding is also is used for the migration to address unicode issues.