SRK still has potential to deliver a blockbuster which will also be a universally accepted movie. It's just that at a certain age, you lose interest with the movies because unless you get a solid script, it becomes pointless to go for it. For a 55 year old guy who has given many blockbusters and hits and has been no.1 for many years, it doesn't matter if he can give a hit or a superhit.
We don't remember how many flops Amit Ji has given since 90s but we do remember some of his great works after that like Black, Paa, Baghban, Sarkar etc. Box office success becomes irrelevant after a certain age.