Most likely not
Taking my mates as an example, I'm sure
none of them would be happy to part with $800 for a club membership, so that they can gain access to and relax in lounges.
However, IMHO, this promotion would show them what they could get by being a QFF and motivate the <35 yo's to fly frequently (read
always) with QF in the future and get status, so that they can enjoy the lounge (in addition to other benefits)
The return on investment of this promotion will not be achieved in the next few months, instead would serve as a base to build customer loyalty by inducing/catalyzing the next generation of frequent flyers.
And the thing w/ us, <35 yo's, is that we do a lot of things just because our mates do it. So if anyone in the friends circle is onboard w/ flying QF for all their trips (even if it's very little in a membership year), chances are, all, if not some of the mates would follow suit
I know this because, when we plan a trip with my mates, we
always fly QF and I influence them do so