If I understood the talk correctly, except for the OOP+FP part, DeGoes seems to be arguing out of practicality, not correctness. He correctly argues, for example, that "FP + OOP in a concise language" is irrelevant as a marketing/business speech for Scala. He seemed to me to actually want to make those compromises and engineering decisions you mention, while maybe admitting that the existing ones are not as successful as initially hoped for.