Flexible (economy/biz/first) tickets are expensive on most carriers. If flexibility is needed, it is not clever to buy AY campaign/basic/light ticket types, nobrainer, not?
It would perhaps help in speculations to know the exact ticket types purchased for the trip above.
The ticket type I bought was basic for both legs for this particular trip. Both basic and value allowed date changes and even cancellations just that the fees were slightly higher for basic.
I do try to pay more to be on value ticket type (although even value wouldn't have helped in this case because there is zero availability for both basic and value for 2 months) but for routings that don't originate from Europe, the jump from basic to value can be just outright silly sometimes. The price of my basic ticket booked 6 months in advance was already ~ 1300 EUR (2000 SGD) and AY was asking for 2000 EUR (3000 SGD) for value and 2600 EUR (4000 SGD) for pro. It would have made more sense for me to book a J award ticket outright with other OW carriers like CX/JAL vs paying 2000 EUR for an economy ticket with AY and save myself the frustration of monitoring if the upgrade vouchers cleared (out of the 2 outbound segments I flew, only HEL-JFK got upgraded last min and my remaining 2 inbound segments are still on waitlist...)
Now I can understand if there is no basic/value availability if it's peak season and flights are very full but this does not appear to be the case at all. I have the flexibility of moving the flight to any date in Jan but there is simply no availability on any date in Jan and even Feb (did not check beyond that).