This migration took the industry years because it was not that simple.

> This migration took the industry years because it was not that simple.

It was not that simple, but it was not that hard either.

It took the industry years because Python 2.7 was still good enough, and the tangible benefits of migrating to Python 3 didn't justify the effort for most projects.

Also some dependencies such as MySQL-python never updated to Python 3, which was also an issue for projects with many dependencies.

Maybe his application was an hello world!