I should have offered the third option – nothing has changed (as in this case).
In your position, I would try to tell other owners that by ignoring this issue, they are making themselves vulnerable for future expenses – such as, if a new owner buys the apartment and demands that the owners corp maintain the A/C as it is on common property.
As for costs, a majority of owners can instruct the strata committee NOT to hire lawyers and make it clear that if they do so, it will be at their own expense. The law is unusually clear on this and any owner at any time can raise the issue at NCAT and can even take the committee to the Tribunal for failing to fulfill its duties under the law.
I wouldn’t waste another breath on arguing the point. Take it to mediation (which is compulsory) then to NCAT. And get the complicit committee members and strata manager removed while you’re at it.