Follow this logic. Why are you told to lay still and not make noise and what happens if you agitate the bear? Does it not then stand to reason that if anything the spray worked to further agitate the bear and led to worse injury? I think so. Tom Smith, Herrero, and Higgins tend to guess at the question in favor of their bias'.

And for the record straight from Tom Smith in an email to me: "Importantly, our study did not pit bear spray against firearms… that’s a media creation that I have to undo best I can in interviews. We carry guns and we carry bear spray. This paper merely analyzed the efficacy of bear spray with no cross comparison to firearms. You can read through the study to get a feel for the criteria (please see attached) and feel welcome to ask any further questions you may have later." I did and it was biased in several key ways that lead me to openly dismiss it every chance I get.

Bear spray has it uses, including attracting bears, but it cannot replace the lethal option.