Regarding the increased incidence, that is supposedly a statistical fact as. On the other hand, it is hard to know for certain, because we mostly have proxy data about this (number of ER presentations, number of insurance payouts, Medicare/Medicaid costs, police reports, etc) and proxy data can be influenced by other variables (e.g. people are more educated about tetanus/rabies, people are more litigious, insurance is more prevalent, increasing healthcare costs etc). I think deadly attack data is more reliable and temporally robust, and that shows an increase as well.
So I tend to give credence to the idea that there is a trend towards an increase in incidence. On the other hand, the data I can find is too poor quality to try to use it to explain the factors behind such increase in any meaningful way.
On the other hand, I tend to be careful about ascribing a mystical explanation to poorly understood phenomena. This is one of the most common things pointed out with glee by advocates of scientific materialism - the so called "God of the gaps" argument. It goes like this: religious people tend to immediately provide a mystical cause for poorly understood phenomena, then scientific inquiry finds the actual proximate cause and hilarity ensues. Of course, the issue remains that scientific inquiry never finds ultimate causes, but that is a different discussion.
In this case, I would postulate that as people, at least in Western countries, become progressively more attentive to global issues and virtual relationships and progressively less involved in day to day real life, all their real relationships, including those with their pets, suffer.