The whole shred thing is pretty simple. If you're willing to put the time in to sit there and practice scales, arpeggios, and three-note-per-string patterns, every day for hours on end, then you're likely to develop blazing speed ... doing those things.
To a point, that's true. I mean, I consider what technique I have a testament to this.
However, past a point... I know VERY few guys who have the kind of technical aptitude you see in a guy like Rusty Cooley. Anyone can build a moderate amount of speed, enough to play some pretty flashy runs, but to play at these kinds of speed, well, I've been practicing for years and I'll say pretty objectively at this point that I'm never going to be as fast as Cooley, and odds are I'll never be in the same ballpark.
That said, it's also pretty easy to knock speed for the sake of speed (and I'm with you there too, if it's not musical it's crap), but I feel like a lot of guys who get the "shred" label get unfairly written off simply because they play fast. There's a ton of YouTube bedroom shredders who don't do a thing to help this, but if you look at the truly gifted players in the "shred" thing - guys like Joe Satriani, Steve Vai, George Lynch, Neil Zaza - you'll find that while they have amazing technique, they also all have powerful and immediately recognizable melodic sensibilities.
Lynch is a name I almost dropped in this thread, simply because his phrasing is so off-the-wall. His first solo on Tony Macalpine's "Tears of Sahara" off
Maximum Security is one of a handful of solos I've ever tried to learn note for note, and one I've absolutely failed to do so simply because I absolutely cannot cop his phrasing. I can do a passable imitation while improvising, and I consider him a huge influence, but I just can't get it down note for note because it's so strange - he plays around the beat a little, and he never quite lands on a note evenly, either sliding into it unpredictably, bending it slightly out as he holds it, or scooping the bar slightly and rising into it. His inflections are just masterful. Sure, he's a shredder, but I don't know many blues guys who can inflect one note in that many ways. You gotta start talking about guys like Albert King (one of his solos, "Personal Manager," I think, has him playing one bent note for an entire chorus, and making it sound different every time he hits it - genius) before you find a peer.
To be fair to Cooley, I think his debut he felt like he had to prove something. Outworld, too, is pretty balls-to-the-wall technique, but he's showing a little more of a melodic side. I have a feeling over his next couple albums he's going to mature as a player and his solos will be less of a technical tour-de-force and more of a musical statement that happens to use blistering technique. If he ever gets the full package together, he'll be just mind-numbingly good (not that he's bad these days, exactly, lol).
