Think about some of the formats we had in the 70’s and 80’s and how often people actually have that hardware and software in working order now.

Well yea, but it's a matter of funding and business/government desire. 99% of the time the only people who care about accessing things that old are hobbyists and enthusiasts.

If something critical to a fortune 500 company or government was stored on it and they needed it they would have the means to contract out a specialty one off device just to read it (Or contract out to a very pricey data recovery shop)

And software is software, we can still run 70s and 80s software through a myriad of virtualization technologies fairly easily and cheaply.

Aren’t most of those emulateable in dos-box or similar programs?

That's for future people to figure out

Last year I ripped my whole DVD collection.

Blu-Rays were more of a pain because of the format itself; Handbrake itself wouldn't do the job, I had to use MakeMKV to get a huge mkv file then wash it through Handbrake to compress it to an mp4. Not a single one failed.

Movies on DVD, out of ~300 discs, I had a total of 6 fail because the discs are somehow damaged, most were visibly scratched and wouldn't play back in a normal DVD player either.

TV shows on DVD, out of ~150 discs, ~40 of them partially or totally failed, many had visible disc rot. And there was definitely a pattern that boils down to "cheaper discs tended to fail." Older discs from earlier in the format's life proved more reliable, I think because, for example, my copy of Friends was purchased in the mid-2000s relatively early in the "TV shows on DVD for binge watching" era, some 60 discs in total, no failures. Smaller runs of shows that not a lot of people bought that were kind of plunked out on DVD for the nine people that bought them like Kolchak: The Night Stalker or The Greatest American Hero? 50% failure rate. An interesting one is my copy of Stargate SG-1. I own some seasons from an earlier pressing that came in individual standard plastic cases in a cardboard box, you know what I mean? Those were reliable, only one disc failed because of scratches caused by mishandling. I own some seasons from a later re-release in those slimmer 5-discs-in-a-cardboard-foldy-thing, and more than half of those are unplayable due to disc rot.

Meanwhile I have CDs made in the 80's that still play just fine.

They last very long as long as no humidity catches it tho.

Bluray and uhd bluray are the current standard

Does the 'original speed' mean what the natural playback would have been? So 60 minutes of audio burned by a x60 drive would take one minute?

I am unfamiliar with the math used to calculate that value.

Would it not work like a parity RAID where each sector would have parity bits in a different location on the disc?

Or like a UMD or mini disc? Still have to insert it into something to read and write, but the discs themselves are enclosed and protected unlike CDs and DVDs and Blu-ray. Basically they're floppy disks, but instead of magnetic tape inside the shell, it's an optical disc.