I have to add my observations to this. I have seen one or two people who have no clue what scale or chord they just played, and yet they sound awesome. However what i noticed about these people was that after a while, their sound became repetitive. They usually just memorize a whole bunch of lines and throw them at you really fast.
That's because they're probably just parroting what they've heard others do.
Not that it is a bad thing, but if it's all you know it can be limiting.
Just like with any language: if all you do is speak and repeat what you've heard others say, but avoid learning how to read and write and use a dictionary and thesaurus and other things that would increase your ability to communicate, you limit what you can say and how you can say it.
On a related note: there seems to be this aversion to learning "theory" by a lot of guitar players. They see it as some sort of crutch to improvising and fear that it will hinder their ability to "feel" because they might be thinking about scales and chords and keys and all that too much.
Can I just say that I believe that idea to be a complete lie and a sign of mental complacency.
Many excellent musicians I have known or read about all say the same thing: learn ALL you can and then forget about it and just play. By learning all the theory you'll be able to store up a ton of information which you will be able to use when creating music and you won't have to think about it. It will just flow out of you and instead of a trickle of water from a spigot, you'll have a flood from a waterfall.
In my humble opinion.
