The critical crossroads for both iconic performers are nigh upon them. They certainly realize that past performance doesn't guarantee future success and in fact makes them prisoners of stellar achievement. Question is do they have enough left in the tank to sooth the naysayers? The "what have you done for us lately?" echoes are growing louder by the day. At the time of publication the author had no position in any of the stocks mentioned.Follow @arnettrickThis article was written by an independent contributor, separate from TheStreet's regular news coverage.