In some sense, everyone is adjunct. People who work in industry have fixed-term renewable contracts. If job security is to be offered, extend it to other professions as well, as French do (with their CDI contracts).

The main point is, professors don’t need life-time protection in many fields where research is increasingly focused on obtaining results in short term, and has become money driven. The gap between the type of research in academia and industry is not that much in many areas.

Perhaps a 5-years contract model would work better: a performance review every 5 years. Professors get some job security if they want to pursue problems sometime ahead of the industry. The duration could depend on the field.