This debate gets really old. Everybody agrees that the Suns need to add a big? It is generally agreed that PJ Brown would qualify. So why don't we talk about what is really going one - a battle over money.
Yes, there is a chance that PJ really really really wants to retire and just wants to torment us. "I really hate thos Suns fans. How about I stretchthis out as long as I can so they can spend their summer in misery and prevent the team from signing somebody else".
IMHO, what is much more likely is that he knows perfectly well that the Suns need him and have plenty of cap space. The Suns don't want to spend a lot due to the luxury tax, but figures eventually they'll give in and up the ante.
IMHO, the Suns think he wants to play but is trying to pull more money out of them because he figures he has the leverage. They're pretty sure no one else is seriously in the bidding above the veteran minimum.
So rather than fret about playing the season with Marks as the only backup big, why not simply accept that this is about money. Sarver's reputation for being tight actually helps in the negotiation if PJ is just after more money because he'd know a s "softy" would give in.
Obvioulsy if PJ signs elsewhere or makes an absolutely retired declaration, then we can criticize the Suns FO and say they've messed up. But criticising them for taking a negotiating pose seems to me to be absurd.