The subject of fuel NOTAMs has been discussed @ RAPAC over the years. There have always been complaints about the number of NOTAMs overall. Include FIR NOTAM (as you normally should check), and you have many pages.
Many locations do not have a NOTAM service per CASR, so NOTAM can't be issued anyway. Only authorised persons can issue a NOTAM, and at country ADs that is usually only the AD OPR.
There was also feedback at one point that many refuelling agents did not want the responsibility of arranging, amending and cancelling NOTAMs, their feelings being that pilots should contact them to ascertain fuel and their availability, callout fee etc.
The regulator - CASA, not Airservices - position was that the introduction of issuing NOTAMs re fuel could lead to the interpretation of no NOTAM = fuel available, which may not be the case, and that instead NOTAMs should not normally be issued and the practice of pilots telephoning to ascertain fuel availability should continue.
If the policy has changed, the practice of arranging NOTAMs may not be widespread (and I'm not sure a requirement could be imposed on refuelling agents anyway), so common sense says never rely on whether or not someone has issued a NOTAM.