Because Pep doesn't operate the way most people do, IMO. He's not driven by money, plays things very close to the vest and is obsessive about all aspects of any project he might choose to undertake. So, it makes it difficult to assess his leanings one way or another.
My best guess on which way I see him leaning based on what I've seen of him over the years, City ticks most of the boxes I imagine he's looking for. It doesn't tick all of them but not sure there's a job outside of Barcelona that would.
He's definitely going to the Premiership, I think that's a foregone conclusion otherwise the sabbatical in NYC to work on English for him & his family was an odd choice. He'll need an ownership that will not demand immediate results or interfere which would rule Chelsea out - regardless of how much Abramovich could profess to change for him. Liverpool has history, great fan support and a decent youth setup but are paupers in the transfer market. United ticks boxes that City can't but SAF doesn't give the impression he's ready to call it quits. Moreover, an inferior youth program setup (Compared to City) would require the Glazers to spend more than they're accustomed to.
City has endless funds, great support for a manager, an impressive youth setup & facilities and Barcelona management already in place. It lacks the pedigree of what I would imagine he'd be seeking but that too has it's advantages as he could develop a mystique for City.
The only other possibility I can see is perhaps Arsenal but who knows, maybe he'd go the route of Laudrup and choose a small club. That's just how unpredictable Pep can be