I tend to disagree with the statement that you've already failed if you decide to eagerly load resources before they are used or needed. Take queue from Google or others who pre-fetch resources based on anticipated usage. In the world of SPAs and client-side heavy apps, combining resources into a single or logically grouped set of resources is common practice to cut down on the amount of overhead that many http(s) calls impose.

Also, the intended use of PleaseWait.js doesn't have to be used to stall while client side resources are brought down. This concept could easily be used for long running, server side processing.