IMO it boils down to the personality and image of the musician.
A lot of the guys from the 80s shred era were all about being larger than life, to the point where they could've easily overshadowed the vocalist in the spotlight. Of course add to the whole excessive rockstar lifestyle from back then that barely exists now for the mid tier bands, it's easy to differentiate the old vanguard playing in packed arenas inspired by all the virgins in the crowd they want to deflower as opposed to the modern day guitarist playing isolated in front of a camera inspired by one virgin, namely himself.
Granted that there's plenty of modern day guitarists that are chock full of personality. It's just that for most of the old guys raised with the classic almost 'gunslinger attitude' we may not find a lot of the new guys and their personality appealing. To use Guthrie as an example, obviously the old mentality is gone, but I like his 'dry Englishman wit' that he portrays both on and offstage, as it's humbling and keeps everyone grounded. It's a different kind of aura, but an aura nonetheless. Though he also has an advantage of playing live as often as possible.
Part of the personality lies in the visual aspect, which I find often gets lost in the youtube crowd. The amount of faceless guitarists who, while play as note perfect and robotically as possible, they just stare at the fretboard with barely any effort on the visual point, thus being as charismatic as a doorstop. Any attempt in trying to do so, can lead to mixed results of either looking embarrassing or ironically awesome depending on the viewer's tastes. And there's a huge difference between a roaring crowd to a view count.
There are some guys that transcend that for good or for ill. I only heard of Angel Vivaldi from these forums and youtube and he drips with unique personality. He also plays live often too. And there's the other guys who incorporate humor into their content, be it making silly joke faces, mocking the stereotype, dressing up as an anime maid or playing with a shovel... not my tastes personally, but I respect the effort in bringing their personality to the forefront.
On the flipside, I'm sure there's a countless amount of facesless EVH clones from the 80s that never went anywhere because they had no charisma and personality whatsoever. These guys didn't have youtube so we weren't so exposed to it back then. It's not much different from today really. Trendy guitar player du jour followed by a legion of imitators, with very few ending with longevity after they transcend the trend.
As always, personality and image are everything.
EDIT: In terms of songwriting, my recent favorites come from the guys at G5 Project and G.O.D (Guitarists On Demand), where it's all about melody. Some I prefer over others but all have a great sense in making music that isn't just about showing off guitar technique.