I understand the desire for structured packages, but even in languages like python that have 'the python way' or what have you, there are still plenty of packages that don't quite fit. This isn't a problem with python, it's a largely philosophical/religious issue that has much to do with the idiom or mindset of the package (or likely the maintainer) at hand. But still, i don't see this as a problem that
javascript has to address rather than say, a problem that
libraries have to address.
You see this all the time in even jquery packages: are they $.pkg.method(elts) or $(elts).pkgmethod() or is it $(elt).pkgmethod(spec) or .... and so forth. Part of it is a matter of taste even if sometimes it goes against 'the jquery way.' Again, this is so religious that it's often not even worth fussing over.
Blaming browser vendors or our ecma overlords for package standards seems like a bit of a straw dog because javascript isn't a package distribution mechanism, it's a programming language. If you want to build apt/npm for browser js via require.js+jquery or your combination du choix, then by all means, but this isn't a failing of the language just as brew failing to install mutt is not a failing of ruby.
Certainly, there's bound to be some overlap in packages, but this happens everywhere and who cares? underscore+jquery seems like a strange example especially when the two are complementary. If the goal is to have a "lightweight core" with "components that deliver specific, isolated functionality" i mean, aren't we there right now? And for where we're not, as mentioned by other commenters, coffeescript and friends certainly seem to be fighting the good fight.
I'm all for innovation, but i could do without "enterprise javascript" (isn't that was es4 was and, i mean, i'm not exactly losing sleep over that decision). For proof positive that we're already getting the 'roll your own' strategy, check out the modernizr 2 beta (or, the less modest jq-ui).
If the point of modern js is that people are working together and optimizing, then yay!! but if the point of modern js is that we need to abide by some static discipline where each function only accepts a single spec object and conforms to some require.js loading protocol then, umm.. thanks but no thanks.