Would AV1 have been possible in 1993 when MPEG-1 came out? How would you have bankrolled the standard at the time?
No. There weren't enough transistors in the world. I'm not being silly. Something like Av1 happens now because Moore/Dennard allow it to.
I think it's widely understood that the technical innovations in sixth-generation codecs like AV1 were simply not computationally feasible on circa ~1993 devices, so I highly doubt that's what was meant. Therefore I'm not sure how transistor density relates to funding models for DSP innovation.
When Xiph.Org started (1994), even audio required high-end hardware. Yes, sound cards were available for PCs, but big enough hard disks were not.
When only the elites have access, the standards are made by elites.
So perhaps the cutoff year of 1993 is right before the threat of non-pooled patents was well-publicized.
There was a lot of video codec innovation back then too, but everything aside from the MPEG or ITU-T codecs was proprietary, and everyone took out patents. To Monty's point, the sheer number of endpoints capable of consuming digital video whose consumption somehow results in income for the publishers was just not quite there, making an alternate push for deriving revenue from DSP IP than patent licensing fees much less likely.