We're talking about static files, right? If you're trying to scale those should be nowhere near your application server. They get served from a CDN and the size is completely irrelevant to technical scaling issues.
Money is easy. It's not part of the difficulty of scaling. 1000x the static traffic means 1000x the bandwidth heading to simple, independent, easy to load balance servers. Difficulty added per user: zero. Cost per user: the same or less.
There are many reasons to want small files, but scaling isn't one of them.
A one time cost in a universe where your app never changes, CDNs cost nothing, and browsers have perfect caches, and everyone ubiquitously uses the localstorage and app-cache html5 apis.
