Will/Can Metallica ever go back to its old glory?

Up to about 1991, Metallica was the greatest, most glorious thrash metal/heavy metal band in the business. Best percussion, best guitar, no question 'bout it. Then after '91 things went sour and they went down hill. They started writing shitty emo music and they did what every other rock band at that time did. Then in 2003 they really put the nail in the coffin and went over board with horrible percussion and no guitar solos. So, that's they're history. Can they and will they ever go back to the music that made them popular? Or are they going to follow the herd (Korn, Strapping Young Lad, etc...) and make music that no one really likes?