Define calamity.  Capital controls, confiscatory taxation, bail-ins are all good for XMR.  These are foreseeable, known unknowns. I don't anticipate that they will be dominant factors in valuation until after the known catalysts have made their primary impact.

Regarding knowns: Look to AML/KYC and contraband use-cases.  Some consider that history has proven the war on plants to be a calamity, which we are already experiencing in the fullest.   I think that will be good for 25x-50x gains in XMR if/when software usability and risk-aversion demand align. 

Then there are unknown unknowns, unforseen use-cases in which privacy makes the difference between a dark world of calamity, and bright open spaces.  If I were to name them, they would no longer be in this category.  Very hard to discount, therefore.

It's not literally "exponential" until the factors are seen to have compounded.