It's not 10 years, just 2-3 years. Python3 for the longest time was not useable. Only with 3.3 it became stable enough, and it took until 3.5 until it was even

It's not 10 years, just 2-3 years. Python3 for the longest time was not useable. Only with 3.3 it became stable enough, and it took until 3.5 until it was even good enough and many libs were ported. On top of it, Python2 works so well and python3 introduces so few advantages that doing an expensive port is just not feasable for many codebases. And I guess that python is used mostly by smaller companys with constantly lacking manpower and money plays also an important role.