What did these others add to Bach? A richer palette, a looser sense of variation, more color, strange instruments, like the mandolin, lute, the guitar from Spain from I can't remember who. Bach is not what you call music to dance to, and yet the sense of motion in the Italians was very great. They added something like a little swing to that Bach thing.da, dot da da, da dot da da... Getting into Bach is like getting into Coltrane. Can't explain it. The real philosopher beside Monk, was McCoy Tyner who is still at it:
Click on the New CD/DVD for a ten minute update. McCoy was Trane that you thought you heard....(A personal observation, not shared by all)
A lot of people have a hard time getting into the baroque period, but once you do, you get great returns for the effort.
As for the Bach revival. From Andre Gide's journals you discover there was an on going revival of the baroque masters in the first couple of decades of the the 20thC that went along with the early modern masters in France and Germany.