I never really thought they were relevant. Melodies are relevant, and can show off your skilly playing if they are intricate enough and tastefully fit in (like the typical conversation between singy part, and guitar bit for punctuation for instance between lines).. but dedicating some kind of formulaic 8 or 16 bars to "show off" kind of thing just seems silly, doesn't serve the song, the groove, whatever.. its just some dude showing off. I look at "sweet child of mine" by guns n roses as a great example. Yeah its not a super terrible difficult guitar part with the signiature riff, but it is skilly, and appropriate, and creates the mood of the song... the "breaks" with the solos coming in and out between verses and stuff are just kind of filling up space, and it all gets back to rocking once they get back to that melody. Hey, radio wanted 3.5 mintes or whatever. I like melodic playing, but think it is most powerful when it is part of the song canvas or whatever you would call it, intertwining with other stuff instead of being on top of it saying "CHECK ME OUT I'M AWESOME! (with some fast fingers and no particular reason what it adds to the musical composition other than being in the same key)". Guitarists will say "NO! I have feeling and stuff..." about it but really its just some hammer ons, scale runs, taps, whatever... like you are just trying to show off "yeah i know how to play" though instead of serving the song. There are exceptions (and taste is individual so appologies in advance for my picks but the Hendrix or Gilmore or Eddie solos often were as intrinsic to the song as the vocals, where that was the highlight, not the filler. When they become filler, its like "yay... another person knows how to sweep pick a scale" kinda distraction.