Sony Playstation Network. Why is it taking 4-5 days to download a single free game for Playstation + subscribers?

Aware of that. Updates are in the several gigabyte range, I've been working intimately with, even troubleshooting PC's for over 25 years. Math is not the problem! It does make sense. I have a broadband connection at up to 3 GB per second.... Even at the worst it's over 300KB that is BYTES, not bits per second download speeds according to Microsoft speed check. It's that the updates are so enormous... not in hundreds of megabytes.... but billions of BYTES. If you do NOT have PlayStation 4. you probably won't comprehend what I'm talking about, These game consoles require software anywhere from 30 to 60 gigabytes in size. One of the reasons that you can only load a few games on the standard 500GB hard drive and the reason I upgraded my brand new PS4 to one terabyte. Is it because systems today have so much storage capability that programmers can now get sloppy in their programming?

The download speed depends on your internet, it has nothing to do with Playstation's end. What is your download speed? You can roughly estimate how long downloads will take with basic maths.