Totally disagree. If they had learned to play the 'right' way, it's highly debatable that they'd have developed their particular style at all, you'd just be left with some kind of generic Berklee 'cookie cutter' session player.
You don't need 'perfect' or 'correct' or 'right' technique (whatever the hell that actually 'is') to play Jamerson's or Dunn's lines. But to come up with them in the first place, you DO need to be James Jamerson or Duck Dunn.
Without getting into a tedious semantic debate about this - and I do see your point by the way - I would just say that there's too much general ambiguity and confusion about what we mean by "style". It consists of a lot more than just having an idiosyncratic playing technique, and entails numerous non-physical, conceptual musical elements - including one's unique compositional "voice", one's note choices, one's improvisational approach, and much more.
Therefore, it is perfectly possible to achieve a highly distinctive, unique and even unorthodox musical style...yet still adhere to solid, fundamental, widely-acknowledged principles of good technique...

MM