IMHO the problem is that "oversupply" is either a normative statement - it's a surplus relative to some idea of what it should be - or a nearly trivial statement - it's a surplus relative to demand and many scientists are thus underemployed. I agree with the latter as a matter of fact, but it is a trivial claim because financial demand (eg: funding and positions, under whatever structure, industrial or academic) is downstream of normative decisions like the former interpretation, rather than exogenous.