I don't think I entirely agree with that.
A new stadium in a new area would probably generate some new fans from there. They may be the new plastic fans of clubs like Chelsea and City , but their money is still good.
I think the overwhelming majority of Everton supporters will continue to support. They will bitch, moan and threaten but ultimately they will follow, within reason. At this stage of my life Everton is part of me and I can't imagine how I could rid myself of it.
The overwhelming majority of income is from TV and as long as Everton stay in the premiership that will continue .
A new stadium anywhere will offer opportunites to make additional monies that Goodison doesn't offer.
The new owners can only be better at generating income streams and increasing the fanbase worldwide.
I think Everton fans are locked into the notion of Goodison or surrounding areas, new owners just may not care about that for reasons mentioned above.