Casey Muratori and Jon Blow are both hyper-dogmatic "my way or the highway" types, and, crucially, neither of them has built any of the super high fidelity types of game that would require that level of optimisation. They're basically influencer types.
Dunno, the Witness had gorgeous lighting. Both have consulted for AAA too.
Casey worked on tooling for AAA games that most certainly needed “that level” of optimization.
Jon Blow worked on numerous AAA games that required “that level” of optimization. And he’s one of the very few developers in the last 15 years who have managed to sell more than a million copies of a game running on a scratch built 3D engine.
You can disagree with their opinions, but they certainly have the experience to back those opinions up.