Obviously the more learning is necessary (and on good jobs it is) the more it makes sense for a company to minimize its cost, hence going for fast learning folk

Obviously the more learning is necessary (and on good jobs it is) the more it makes sense for a company to minimize its cost, hence going for fast learning folks. If a company hires for learning ability then it is a good prognostic for your learning on the job. Conversely if the job ad specifies software versions to the third dot and years of experience going longer than a technology exists then you might not learn too much there.