Comparing to the industry's best and saying that anything less is unacceptable is the unacceptable part
GG, Rockstar, ND and etc. are anomalies. Imagine comparing every open world game with RDR 2. Not everyone can be Rockstar, and thats ok.
Horizon had Decima engine powering it, arguibly one of the top 3 engines available today. Also had 5 years of dev time fully committed to it, while Insomniac also was making R&C and MM while developing S2
Horizon has huge dinos, but not a full modern city to render, so they have totally different priorities to render stuff
There's so much more to it than just "lazy devs". And again, even if it were just Insomniac lacking tech talent, comparing it to the industry best wouldnt be fair 'cause again, being among the best aint easy
The game will still look better than any other 3rd party open world game, I imagine