Politically and economically, online education would gain traction if it could be offered at a lower cost without test scores being affected. In this framing, your question is one of assessment. The more persistent query would be whether the kind of knowledge that online education is capable of transmitting is the kind of knowledge society needs.
Perhaps you are establishing a false dichotomy - what is to prevent a university system (even a classic one - not sure how you define it) from being offered online? We are not talking about a replacement here - but a shift in the mode of delivery. I have delivered university courses solely face to face, in blended mode, and solely online, and in each case belief that the quality of instruction was equivalent.