After a bit of searching the FAA NOTAMS I found:
1) NOTAM for KVM-70 Honolulu VOLMET which confirms that outage:
A1494/18 NOTAMR A0259/18
Q) PHZH/QSVAS//////
A) PHNL
B) 1804151522
C) 1904151500
E) VOLMET FREQ 2.863, 6.679, 8.828, 13.282 U/S
2) I did not find a similar NOTAM for WSY-70 but I did note on Hepburn's
http://dxinfocentre.com/volmet.htm web page notes to the effect of outages for both Honolulu and New York Radio. Hepburn while not an "official" source is usually very reliable.
Perhaps I just did not ask the FAA NOTAM server the right question or perhaps that Gander VOLMET covers a similar geographic area and shares the same frequencies then the requirement for a NOTAM is a bit different or perhaps the NOTAM was issues in a different manner.
I think VOLMET broadcasts are going to continue to be important because they permit the transmission of AIRMETS and SIGMENTS in an automated fashion that reduces the operator workload on other HF and even VHF frequencies for flights departing from or approaching mainland areas in the same way they use ATIS for flights departing or arrival at airports - that is, the controller or operators will ask if they have (for example) SIGMENT ALPHA, if they don't then they will need to read it to them otherwise if they do they can then skip that bit.
Times are changing however, CPDLC (i.e. datalink) is becoming the primary method and HF is fast becoming secondary for much routine communications.
cheers, Graham near Ottawa Canada