x265 is just objectively better than x264. I'm not sure what's to poll. It really comes down to the encoder themselves which ends up a better result. x265 has a minor draw back in that it's new and older things don't naturally support it and a decent draw back in that it takes more CPU power to decode the stream for playback. Other than that though x265.

The various quality though comes from inexperienced or lazy encodes for both formats being available. I have such a pet peeve for someone taking a x264 encode and uploading it in x265 with like a 2% file size reduction and talk about how much better it looks. And the general downloader eats it up because 'x265 gud' to a certain degree. It hurts because then that typically becomes all you can get and no conversion is truly lossless so even re-encoding them myself can take a lot of work to get the reduction without quality loss. I've seen x265 480p encodes that end up with bigger files sizes than if you encoded the shit in AVI, because they seem to think low CFR and 265 is instant quality at a "better" size. If you take the time to really dial in the settings, run it at a slower speed, and understand what type of content you're encoding you can get an incredibly high quality small file. But that takes a decent amount of knowledge and a lot of patience. That's what really sets apart good encoders/releases.

Idk the fix. It doesn't help there's also people convinced a larger file size has inherently better quality. Like seeing a bluray 1080p rip in x265 that's a larger file than an entire bluray disc can hold drives me up a wall because usually it's one of the more seeded files. Like obviously people uploading and tagging 4k lossless files know what they are providing, those files are needed for the proper encodes to eat up.

But RARBG tagged releases were amazing quality. You typically had to go up a few gigs for similar quality from another release. Pahe can really nail some tv shows. Few other encoders back in the day. YIFY/YTS are amazing for the size, but you are giving up some quality. But you can't beat a 1.5gig movie that is better than streaming quality at times.