Photorealism is unachievable on current game budgets.
So to justify it you'd have to be able to say it would get several times the sales of any game made this gen.
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Realism is actually quite constricting. You can only make games about things that actually happened or are plausible with real world physics. Stylised art allows you to be as crazy as you like, make the game memorable (i.e. not a grey-brown FPS), and do it on a tiny budget.
Mario Sunshine is my benchmark for game graphics. It looks amazing and I need nothing better to fully enjoy a 3D game. Also it's 10 years old.







