The following study has identified 5 different clusters of patients. It was suggested that one cluster was possibly misdiagnosed.
https://academic.oup.com/rheumatology/article/59/8/1906/5632039
Just because people have the same diagnosis of PMR/GCA --- that doesn't mean people respond to treatment in the same way.

You may be interested the Treat-to-target link given by John in his post above. Having searched and considered all available studies, trials and articles about PMR and GCA, they seem realistic about treatment options and durations and don't push for getting off prednisone at any cost. They put most importance on achieving and maintaining remission ("The treatment target of GCA and PMR should be remission; remission is the absence of clinical symptoms and systemic inflammation"), while acknowledging that remission cannot necessarily be measured. [Recommendation 1]

They say also that "in PMR, observational studies suggest that long-term drug-free remission can be achieved in 30%–60% of patients. Tapering off treatment should always be balanced against the risk of worsening disease activity." What about the other 40-70% of us who they acknowledge cannot achieve long-term drug-free remission? [Recommendation 5]

They acknowledge the need to balance risks:
"The treatment targets are achievement and maintenance of remission, as well as prevention of tissue ischaemia and vascular damage." [Results]

They put forward over 20 items in need of further research. There's still a dearth of information regarding PMR and its treatment.