1) Very few people are going to go through the hassle of sponsoring an overseas worker for a junior role. It's a pain in the ass. I think this is an issue that is hugely over stated.

2) I don't know if you remember this but back before everything was a crud web app they were crud desktop apps. Most development work just isn't ever that exciting.

Lastly you don't consider at all that demand has outpaced the pipeline.