Why does the bluray transfer look so good?

"Are you talking about the 4K transfer or the regular blu ray? Because if it was the later version it wasn't anything to write home about."

Yes, it is. The Blu-ray transfers of all the old Rocky movies (parts 1 through 5) are excellent; among the best looking transfers out there. They are clean, sharply focused, have little-to-no DNR, and have excellent color timing. You must be one of those people who thinks film grain is a flaw, and that waxy YouTube videos is how things should look.

Are you talking about the 4K transfer or the regular blu ray? Because if it was the later version it wasn't anything to write home about

What?? Just watch the DVD version and compare it to the Blu-Ray, it is another world. The resolution is so clear and the colors are so much more distinctive and bright.

I guarantee you, I have both the DVD and Blu-Ray versions and the difference is obvious.

This. Plus 35mm analogue film arguably produces a much more flattering and cinematic image than even the most expensive digital cameras, so seeing old 35mm pictures scanned with the latest technology might even be preferable to 'new' movies.

Exactly this. Movies shot on 35mm film really shine when we see them in a higher definition format. Remember that feature films were meant to be viewed on a huge screen.