Can the Blandford–Znajek Mechanism Power Steady Jets?

We consider the Blandford-Znajek (BZ) mechanism for extracting black hole spin energy to drive astrophysical jets. Analyses of BZ generally take no account any electric charge on hole. But, as noted by Wald and others, if medium surrounding is an ionized plasma with mobile charges, then a spinning quickly acquires charge. The effect this nullify field structures which mechanism. Since jets are now observed in wide variety classes accreting objects, most do not contain central hole, it seems likely that jet driving all objects uses directly from accretion disc, rather than spin.