I happen to agree with the article. The added expense of and complexity of an ICE plus largish batteries for decent AER will become cost prohibitive. The amount you pay in reduced efficiency and added maintenance would pay for the occasional rental in the outlying case of 400 miles of EV range not being sufficient.
It is inevitable that battery costs will continue to decrease, but the cost of the ICE and related components will not (mature technology to say the least).
This article is not stating that there is no market for PHEV's today, but that the market will continue to decline in the future. And yes, some will continue to want/need a PHEV over a BEV, but the cost differential is likely to reverse at some point and a PHEV will become the more expensive option.
That so many of the issues/complaints about the Clarity (and other PHEV's) are related to the ICE, transmission, etc is at least somewhat of an indicator of the weak point. The Clarity, in all it's iterations, is almost purely a compliance car (the FCEV and BEV are the very definition). While the PHEV version is sold outside of Section 177 States, it would not exist if the TZEV credits were not valuable to Honda.
Every time I read a post about how little gas people used in xx miles/months, it reinforces the idea that if they had "real" EV range (say 300 miles), the necessity for the ICE would be very close to nonexistent. Is this true for all owners? Certainly not. And PHEV's have their place. But as EV technology and infrastructure develops, that use case will continue to decline and offerings by manufacturers will follow suit. I don't expect to see any offerings in the 100 mile electric range neighborhood, but do hope to see a few more that hit the 50 mile mark (which comfortably covers most commutes in all weather).