I think it actually makes sense for something like Ansible to use Python 2 because it's about controlling lots of remote machines on various Linux distros, and the idea is that it's agentless. If you suddenly have to install an "agent" (Python 3) on all the remote machines before you control them with Ansible, that wouldn't be great.
On the other hand, Ansible itself could have a tiny bootstrap step which installs Python 3 on all the remote machines before it does any work.
In our case, we use Ansible daily for deployments, but haven't actually written any custom Python modules -- it's all just straight Ansible YAML. So I'm guessing for a lot of use cases it doesn't really matter what language Ansible is written in.
On the other hand, Ansible itself could have a tiny bootstrap step which installs Python 3 on all the remote machines before it does any work.
In our case, we use Ansible daily for deployments, but haven't actually written any custom Python modules -- it's all just straight Ansible YAML. So I'm guessing for a lot of use cases it doesn't really matter what language Ansible is written in.