I can promise the number of people backing up their Xbox/SNES/Sony/whatever games at the time/era of release, are a rounding error number of people who purchased at all. And even if that was the case, how are you gonna do that for the discs that have DRM? Obviously it can be cracked, but how does that help you in that specific time of need (referencing the house fire), when the tech to crack that DRM didn't even exist?

Nobody is arguing with "physical copies have better security" (digital storefronts closing, keys being revoked, etc), they're only arguing with you for pretending everyone is seemingly clairvoyant, with pools of money and compute hardware, to make backups of these things. There is no way you can possibly think that all one needed to do was "copy da files dumbass" when even the hardware to do that, didn't exist (for the public or at all), or was itself prohibitevly expensive.