Suse, for example, told me it has 66 vacancies at present and will be creating at least 150 new positions this year, all associated with open source software. The company said it will need more than Linux developers; it is hunting for OpenStack developers, Docker specialists, and engineers to build distributed storage software too.
We look at many aspects when hiring, including experience, contributions, and fit into the SUSE culture. Certifications is one aspect, but certainly not the only one.
They should be seen as naught but a crutch for HR people and are an extremely poor filter. They reward the wrong thing, so they select the wrong candidates.