Could it have been that he totally refused to go to Napoli & Pescara wanted the extra cash so the only option was to take him off the market?
Yes. I realise it's a dangerous position to put myself in, but going from all the interviews I've read and seen with Verratti, I'm totally confident there was no way he was going to join Napoli when Juve were still interested.
The player has even stated that Pescara and Juve are his clubs, so it was one or the other here if Juventus maintained interest.
The Pescara president has been playing this game for over a month now. There was an interview with him when he said something along the lines of "a lot of clubs are interested from Germany, Spain, England and Italy like Milan". Casually dropping in names to try and put pressure on Marotta/Paratici to make a bigger offer. Then lately he said that Verratti is a professional and he'll join Napoli, to which I presume there was no change in offer from Juventus and Verratti didn't want to go there, so he remains fully owned by his hometown club.