I would imagine it is not so much about Ansible's general valuation in the industry but about its value for Red Hat (a.k.a -- Red Hat is not buying Ansible for its revenues but for its technology).
The direction in which the technology evolves. That's also the reason why Red Hat hires a lot of upstream developers[1]. It is easier to tailor your services and offer better support (ie: the revenue stream for Red Hat) for OSS when the developers who write it are on your payroll.