Some very good points have been made about advances in bullet construction. Simply put, the biggest reason that the .357 Magnum appeared to be so much better than most semi-automatic loadings at the time of Marshall and Sanow's 1992 book is that at the time revolver bullets were capable of things that semi-automatic bullets were not. By using a relatively soft lead nose, it was possible to initiate reliable expansion without using an overly fragile bullet. Such a bullet would not reliably feed in most semi-autos at the time so it was limited mainly to revolvers. Also, JHP's of the time needed relatively high velocities in order to reliably expand (this is clearly illustrated by the teething problems of early 147grn 9mm loadings). The .357 Magnum was able to attain these types of velocities without requiring extremely light-for-caliber bullets which would not penetrate well.
However, the majority of self-defense oriented improvements in bullets over the last 15-20 years has been geared towards the semi-automatic cartridges for two reasons. First, revolvers fell out of favor with law enforcement in the 80's and early 90's. The larger market for self-defense revolvers became small, easily concealed snubbies and many feel that the recoil of a full-power .357 Magnum in such a gun is excessive. Secondly, there really wasn't much need to improve the Magnum as even with very dated bullets it was already achieving the desired results. A look at some of the most commonly reccomended full power .357 Magnum loadings like Remington and Federal SJHP's, Winchester Silvertips, and Federal Hydra-Shoks will reveal that they are often anywhere from nearly 20 to well over 30-year-old designs. The only two premium bullets I can think of that are not so dated and are commonly used in full-power loadings are Speer Gold Dots and Hornady XTP's but even those have been around for over a decade. The other more recently developed .357 Magnum loadings like Winchester 180grn Partition Gold, Remington 165grn Cor-Lokt, Hornady 140grn LeverEvolution, and Federal 158grn Fusion are geared and marketed towards hunting or are like Remington 125grn Golden Sabers or Cor-Bon DPX and not loaded to the full power. Basically, it took 30+ years of improvement in JHP design for semi-automatics to be capable of the same type of performance already available with the .357 Magnum.
This does however bring up one of the nice things about the .357 Magnum: one does not need to be particularly picky about their bullet selection in order to get very good performance. Even with bullets that were developed in excess of 30 years ago like the famous 125grn SJHP's, the .357 Magnum can still give performance that compares favorably with the premium semi-automatic loadings of today. Also, when modern, premium bullets like Speer Gold Dots or heavier 140grn+ bullets are used, the .357 Magnum can offer reliable expansion with much deeper penetration than is common to most semi-automatic loadings.
However, the majority of self-defense oriented improvements in bullets over the last 15-20 years has been geared towards the semi-automatic cartridges for two reasons. First, revolvers fell out of favor with law enforcement in the 80's and early 90's. The larger market for self-defense revolvers became small, easily concealed snubbies and many feel that the recoil of a full-power .357 Magnum in such a gun is excessive. Secondly, there really wasn't much need to improve the Magnum as even with very dated bullets it was already achieving the desired results. A look at some of the most commonly reccomended full power .357 Magnum loadings like Remington and Federal SJHP's, Winchester Silvertips, and Federal Hydra-Shoks will reveal that they are often anywhere from nearly 20 to well over 30-year-old designs. The only two premium bullets I can think of that are not so dated and are commonly used in full-power loadings are Speer Gold Dots and Hornady XTP's but even those have been around for over a decade. The other more recently developed .357 Magnum loadings like Winchester 180grn Partition Gold, Remington 165grn Cor-Lokt, Hornady 140grn LeverEvolution, and Federal 158grn Fusion are geared and marketed towards hunting or are like Remington 125grn Golden Sabers or Cor-Bon DPX and not loaded to the full power. Basically, it took 30+ years of improvement in JHP design for semi-automatics to be capable of the same type of performance already available with the .357 Magnum.
This does however bring up one of the nice things about the .357 Magnum: one does not need to be particularly picky about their bullet selection in order to get very good performance. Even with bullets that were developed in excess of 30 years ago like the famous 125grn SJHP's, the .357 Magnum can still give performance that compares favorably with the premium semi-automatic loadings of today. Also, when modern, premium bullets like Speer Gold Dots or heavier 140grn+ bullets are used, the .357 Magnum can offer reliable expansion with much deeper penetration than is common to most semi-automatic loadings.