If I cast Reality Ripple with Eon Hub out, is the target Permanently phased out?
Yes. From the comprehensive rules:


  702.25m If an effect causes a player to skip his or her untap step, the phasing event simply doesn’t occur that turn.


If by 'permanently' you mean 'until something is done about the thing that prevents untap steps', yes.
However, if that thing is removed, untap steps will happen again, and phased out permanents will phase back in.