Considering that there were no music videos before the 80s, people didn't approach them with any expectations. Because they were a novelty at the time, none of the artists who made those early videos had anything to base theirs on, so while they might come off as silly today, it's important to keep in mind that people were a lot more forgiving back then because those early videos didn't have to live up to any established standard. I think the music of the 80s tends to get more flak for being so different from what preceded it than because it can be summed up as being generally "bad." Most of the music of the 70s - and nearly ALL of the music of the early 70s, sounded very similar to what people were doing in the 60s. And while music went through a Golden Era in the 60s, if you deconstruct a lot of what was being done, it was essentially just taking what was being done in the 50s to the next level.
But love it or loathe it, the 80s ushered in a completely new approach to music. Many purists decry the prevalence of synthesizers and other electronic elements to the music of the 80s, but I think there was still a lot of good stuff coming out back then. And it's silly to judge the musicians based on what they looked like. There were plenty of talented musicians wearing ridiculous outfits sporting ridiculous hairstyles and wearing ridiculous makeup that were writing good songs.
It wasn't only popular music that was being shaken up, but the rock and roll that had begotten heavy metal in the 70s was born again hard in the 80s and completely different forms of metal sprouted. Traces of rap and hip-hop had existed in previous decades, but it was in the 80s that they took real form.
The 80s was a time of great transition in music, some of it for good and some for ill I suppose, but at least it wasn't boring. Musicians today may not be wearing leg warmers, but I think there was a lot more style and substance to what was happening in the 80s than there is to the mundane autotuned dreck that's made today.