FYI, this is a feature, not a bug. One of MySpace's early differentiators was that it allowed fake profiles, unlike Friendster.
Another differentiator was the extreme level of customization available, which as you note, resulted in a lot of lag because most people do not even realize that could be an issue.
No, Facebook has successfully homogenized the identity of individuals. Every person's page is the exact same professional-looking franchise restaurant. BORING. It wouldn't be the worst thing in the world if people could make their pages individualized in a thoughtful way. Few people are asking them to allow Flash or go full MySpace. Perhaps instead, a library of curated themes, or even fully custom CSS (that could be turned off), a la subreddits.
If you want all of that, build yourself a home page. Tumblr and Livejournal did it right by offering ways to view someone's account with out their idea of what good taste is. Still, between NO customization and customization, I'll take the bland option.
It works great on Reddit for subreddits because if you get it wrong, you can just move to another subreddit or find a moderator who knows a thing or two about CSS.
I can't just up and find friends who aren't fucking colorblind.
For the same reason we joined ICQ in the first place. Hype, incremental improvement, playing with new toys, and some of our friends were there but not on the previous thing we used.
ICQ did suck. It sucked the way most things suck: given the environment and state of the product at the time of release, they sucked less than other things on at least one metric.
I was never around for the Friendster days(I was a Livejoural user through and through, damn it), however the reason I suspect MySpace lost out is that they did do the GeoCities thing. Everytime I see people complaining about a new Facebook layout, I always think, "Is this worse than the best MySpace page?" Answer is always no.
It's not that we're reinventing ICQ or AIM or MySpace or whatever, it's that we're refining the, oh god I hate using this word, "experience" of using it.
Does Facebook have random flash things pegging my CPU to render a cube in 3D with my friend's vacation photos on each face? Does Facebook have auto-playing music? Does Facebook have the option of setting the page's colors to be hideously garish?
I also think Facebook is realizing this, and they're trying to retool their business away from Facebook this website you visit, to Facebook a thing where all of these neat services are wired up to. I don't know if they'll succeed, but at least they have the sense to know they're not going to be on top forever.