Maybe neutrals would support it? A lot of people have moved over from east in the past few years and stayed here. Maybe they support Victorian clubs and want to support a new club that doesn't have the history of the two WA clubs. It's possible I guess.
You might be able to attest to it yourself but many Vics who move here develop a bit of a siege mentality and are actually pretty fervent supporters. I'm not sure how many neutral footy fans there really are here. Not many imo. Would need to target migrants/non-footy fans, a Joondalup-based team makes sense from that perspective as well as a population one. Even then you'd think it's still a good decade at least away from being remotely viable. Might be a different story if you want to work the West Perth "promotion" angle though.