Well... I believe the chance of them buying Airbus product is not very likely... They only buy Airbus product when there is no Boeing prodcut of the same class avaliable like A380 now...
To be honest, Airbus is not 100% wrong... A330 have only been around for around 10yrs... And A350 is designed as a part of A330/A340 family...
As A330 have not be here for so long yet... Replacement is not needed yet as this point... So the demand for A350 wont be very strong until A330 get to a older age...
But A350 is really came out to go against B787... But with the lack of time for Airbus, if they dont use A330 baseline, it wont be able to come out close to B787 schedule delivery date...
Also, with the limited funding that Airbus have at the moment due to restrictions on taking loan from EU due to the EU-US arguement about loan and funding to aviation industry not being settle yet... So at this moment, Airbus is hard to ask EU loan like they have when they launch A380... So they only have limited funding to launch A350...