As Openstack is still biggest solution for building clouds it will still be, because there is not yet a better alternative. The project is mature and even if you read messages about companies dropping the funding, it doesn't mean that they will stop contributing to it or supporting it. A lot of big companies are using Openstack and that means they will also need to extend it, add support for new hardware or plugins and fix bugs that will rise. So as long as Openstack is used by companies like HP, IBM, Rackspace, Cisco etc. it will live.
I found official list of public clouds that use Openstack here https://www.openstack.org/marketplace/public-clouds/.
If you are interested in public clouds I would maybe go rather for GCP, AWS, Azure or any other vendor, because the biggest use case of Openstack is I think in private clouds. And with Openstack in private cloud there might be different job positions that are not only connected to administration of Openstack, but with designing cloud, configuring Openstack components, automating Openstack installation, development and others.
But design, configuration and automation of Openstack installation is whole different story and knowledge you learn there couldn't be really used in different projects.