3 or 4 fingers per string is only used for Spanish guitars (nylon strings) and Bass Guitars... I've actualy never heard of any one who shred on Elec. guitars using this technique,bec the strings are very close to each other in elec. guitars which makes it very hard to use more than one finger per string..

But you can always do fast stuff by using legatos , like Knopfler (dire straits) ...

Anyway, I believe that the Elec. Guitars & Steel Strings Acoustics were made to be played by Pick or Hybrid Technique, Nylon String Acoustics & Bass guitars were made to be played (mainly) by finger style..