Exactly. But AFAIK every Denuvo game eventually gets cracked, so at least we will have the pirate copies. From a preservation standpoint, a dumped ROM is much better than a physical cartridge anyway, since it's more portable and easier to back up. It's the contents of the cartridge minus the physical limitations.
You're forgetting that patent law applies to industrial property across every sector of the economy. This is a technology issue that goes far beyond entertainment media.
I agree with you, we need legal protections - but for the future. Even the E.T. game for Atari has ROMs easily available. It was just too easy up until recently (and still is with Nintendo hardware) to dump ROMs and write very functional emulators. I'd say nothing up to the PS3 era is in danger, but that's a very partially educated guess.
We're not in danger of losing anything. There's no putting the genie back in the bottle. How is passing new laws going to magically detect and erase all the PSX, SNES, MAME, etc ROMs that I play offline from my computer? How is it going to prevent people from torrenting these files through VPNs in countries that don't give a rat's ass or sharing encrypted ROMpacks? Jesus, even archive.org is chock full of retro games. Trying to get rid of ROM sharing at this point is like trying to dry up the ocean with a fistfull of cotton swabs.
Plus, emulation itself is not and cannot be illegal, barring a complete redesign of intellectual property law from its very foundation. Games themselves, BIOSes and encryption keys are protected, but an emulator is, in rough terms, "something that achieves the same result through different means", and if that could be made illegal, then someone could patent the hammer and you'd have to pay a fine for nailing two things together with a rock.
For me, the best way to play so far is the Nintendo DS version. Putting all the menus and most UI elements on one screen really allows you to fully appreciate the art on the other. In fact, even playing on an emulator, I prefer the DS version. I haven't played the Steam release, but is it really any different from emulating the SNES original?