If you believe modelling that actors can see the future perfectly is an advance - which is what Rational Expectations requires.

It's a fudge to try and explain why monetary policy works instantly rather than in eighteen months to two years time. However the evidence of the failure to raise inflation to 2% demonstrates that it is wrong in practice. Unsurprisingly the real world can't see the future perfectly.

Which is why you need advanced automatic stabiliser systems that actually work on the real world, not just the imagination.