I actually agree with the author, certain fields are just very complex to develop a solid understand without proper mentoring and support you would get as a grad student.
That said, maybe the real issue is not the fact we need two PhDs each, but the question I want to raise, do PhDs need to take 4/5/6 years? (I'm not even considering the cases where people, like myself, do a 2 year master program before the PhD...). Honestly, in my humble opinion, it is not necessary.
Maybe universities could develop "industry focused dual PhD programs" to target specifically crazy folks like us :)
This might be something worth to fight for.