No doubt YSBK will remain. For a while.
But if you think it’s anything other than a shadow of what it used to be for GA (including runways, hangarage and maintenance/parts support) at reasonable prices, I’ve shares in the Harbour Bridge to sell you. The ‘emergency services’ operators pay (NSW taxpayers’) money through the nose to Aeria to have any base at YSBK. Heritage hangars bulldozed. Runways bulldozed. You should know the MO, from your experience at YMMB.
And ‘net zero electric and hydrogen-powered aircraft’? Let’s hope the Multifunctionpolis is well-advanced in its research.