Looks like it was built with ASP.NET MVC 4, which has minification and bundling built in. Should be easy for them to take advantage of it... maybe they just ran out of time or don't care.
The bundling features in ASP.NET MVC 4 were at best release candidate and at worst beta until mid summer. I can see why using them may have made some developer's leery. Adding these features now as indicated by several other commentators should not be difficult.