Recently a request came from a more abstract influence on the project to consolidate the
Gulp will have no trouble compiling your vendor and app code into a single file. The benefit of this is it would reduce the number of requests your browser needs to make to a single script request.
However, two files are often used to make it more obvious where errors are coming from if they occur. It also means that compiling your app code is faster since it doesn't need to re-compile the vendor code whenever your app code changes. Typically, the vendor code is more stable so it shouldn't need frequent compiling (or even watching).
Additionally, with the advent of HTTP2 and its ability to do multiplex downloads, concatenating your code into one large file is a worse option. This is because even a small change results in the entire concatenated blob needing to be re-downloaded.