Comment by psb217

Autoregressive vs non-autoregressive is a red herring. The non-autoregressive model is still susceptible to exponential blow up of failure rate as the output dimension increases (sequence length, number of pixels, etc). The final generation step in, eg, diffusion models is independent gaussian sampling per pixel. These models can be interpreted, like autoregressive models, as assigning log-likelihoods to the data. The average log-likelihood per token/pixel/etc can still be computed and the same "raise per unit error to the number of units power" argument for exponential failure rates still holds.

One potential difference between autoregressive and non-autoregressive models is the types of failures which occur. Eg, typical failures in autoregressive models might look like spiralling off into nonsense once the first "error" is made, while non-autoregressive models might produce failures that tend to remain relatively "close" to the true data.