The one presentation I recall from that far back was a bee researcher that basically said exactly what you posted, whenever his team investigated colony collapses from varroa mites (as opposed to poor treatment from being moved to California), they’d find markers for multiple previously unknown viruses. Honeybees were basically having to contend with previously isolated viruses they never evolved to resist, all at once.
I also remember the xerces society trying protest and interrupt his talk because they wanted to blame (and therefore ban) pesticides only, specifically neonicotinoids. I generally really appreciate the work they do, but in this case they really came away as being dogmatic instead of helpful.
What gets less attention though are the many dozens of native pollinator bees that also were/are hard hit and driven to full/near extinction. These species also have to contend with food source loss, because they are very selective about the flowers they will pollinate because the require a certain nutritional profile. I can’t stop viruses or varroa mites, but I can at least recommend planting wildflower mixes native to your local area.
edit Rediscovered some old blog posts I found looking into the issue at the time and found enlightening. It’s a great example of the observation work that makes a good agronomist. Bear in mind these are from 2012, so no idea if they’ve updated their thoughts to something different.
https://scientificbeekeeping.com/the-extinction-of-the-honey...
https://scientificbeekeeping.com/neonicotinoids-trying-to-ma...