When it comes to retro games, considering the sheer number of titles whose copyright have been bought and sold so many times from one company to another, even if you wanted to buy a legit version, the only people to gain are those who own the licence now and those who actually created the title would get nothing. This is the main reason why I am more than happy to copy retro titles.

A lot of this very much depends on which jurisdiction you're talking about. In the UK, for example, the exception for backup copies only applies where the backup is "necessary" for the lawful use of the software, which case law has held does not apply to games. You are only permitted to make backups if the EULA specifically allows it. Similarly, "format shifting" is not allowed in the UK. You can't copy an audio cassette to an MP3, for instance, unless the EULA allows it.

I've noticed that here in the UK it's less likely to find a drive full of ROMs on Amazon, yet US reviewers of said devices are readily available on their Amazon. I'm surprised Nintendo let this slide, or that they go for Chinese based sellers, where as we know 'copyright' is interpreted as a challenge to copy anything and everything for a fraction of the price!

I only stopped emulating old ps2 games on my phone because of this whole copyright issue. If I had the choice to pay sony a reasonable fee for the bios file and the gave devs too for a copy of the rom, I definitely would. Having said this would you say its ethical/legal to download bios files from the internet archive?

Emulation=legal, well...mostly legal, unless the emulator in question is using someone else's copyrighted content. EX: Dolphin emulator which was being distributed with copyrighted Nintendo keys. Which is why Nintendo struck them. But yeah, while emulating is mostly legal, the obtaining of game backups isn't legal 99% of the time like you said. It's piracy. And only goes on as it is with either a big company ignoring it (Sega) or a big company (Nintendo) only going after the distributors, not the individual ROM downloaders. Which could happen, look back at the Napster/Kazaa file sharing days when media companies were actively suing millions of individuals who downloaded MP3s for like £10,000 per MP3 illegally downloaded.

It's up to the property owner to take action to defend their legal rights.

Interestingly, copyright doesn’t seem to have been part of Nintendo's primary legal arguments this time around, against Yuzu. Makes sense, from their POV, to make arguments against which Yuzu had no obvious defence (eg, "illegally circumventing Nintendo's software encryption".)