To the best of my recollection (which may not be accurate) I thought Paizo mentioned they had for the most part pulled out of Origins years ago due to some issues they had with that convention. Are you sure you were not seeing stuff put up by fans, and not Paizo itself? I think Paizo also said they refuse to submit things to their awards ceremony as well (but again, could be wrong on that).
WOTC had said they had pulled out of Origins several years ago as well. It's not Paizo or WOTC, it's that convention that caused them to withdraw their support - I guess there were some issues. Apparently it is now under new management and people were testing the waters again lightly to see if it is worth supporting again.
On the main stairway off the main exhibit area, there was a big Paizo symbol projected up on the wall, and the RPG gaming area had Paizo posters and such, although mainly/all in front of their gaming rooms. Not sure what the rules are for using the Paizo name for their fan organized Pathfinder Society stuff, but it seemed more official. They had the most events running from what I could see with events running up to 6pm on Sunday. If I recall correctly, they were pretty much all the RPG ticketed sessions on Sunday (there were a few others before lunch I think).
Mayfair and Catalyst were definitely the main sponsors of the convention, though.
This has been, and will remain, my main actual "dealbreaker"-type concern about 5E. I'm hoping this is just a factor of Clerics being the only real "healing class" in the pregens, and that in practice, any "healing class" will do as well (or close enough as makes no difference). If we're back to 2E levels of "needing a Cleric", though, gosh, that's not going to fly with any of the groups I play with.
So, fingers crossed that Bards, Druids, maybe even Warlocks or the like can do a "good enough" job.
I wonder if the need for a cleric/dedicated healer will be as high when using certain HP modules or items. It makes some sense in Basic (ah, the legacy!), but I am certainly interested in getting the heck out of that.
I'm going to go out on a limb here.
The spells the heal in the playtest are: Cure Wounds (touch, but high amount) Healing Word (lower amount but at range) and Prayer of Healing (multiple targets in a small area) Heal (large amount back + status removal) and mass versions of the above. Since they all improve with level, if you know one (and can get high level spell slots) you can use them just a well as a cleric can. (No delayed acquisition of Cure Light/Mod/Serious/Critical, etc)
Bards get Cure Wounds, Healing Word, and Mass Cure Wounds (based on the 5 level version, we now know they will be getting 9 spell levels) Additionally they get Lesser Restoration and Raise Dead(!)
Druids get Cure Wounds, Healing Word, Mass Cure Wounds, and Heal. (They also get regenerate and the restoration spells, and probably reincarnate based on the leaked PHB page)
So bards and druids can do the healing job well enough to fill the cleric's role.
Well that sure sounds like official support to me.