i was stating that if a closed system was at all possible, there is no reason we cant reproduce it.
Well, that's the problem: we can't reproduce it.
Which was my whole point. Universal Turing Machines can't be produced either yet most of theoretical computer science is predicated on it. Many well-educated but otherwise foolish people forget that UTMs don't exist and are qualitatively different than what we can produce. A similar story exists with respect to closed systems and thermodynamics. Engineering often assumes closed systems for its equations when no such thing exists -- the errors get buried in engineering fudge factor.
It is dangerous to assume that just because an assumption is pervasive that it has a real existence in our universe. Pervasive myths in many fields of endeavour exist because they have utility, NOT because they are factual in any given instance. For many purposes myth is cheaper than fact, and if there is no harm there is no foul.
You need to learn what is "fact" (to the extent that such things exist) and what is "pervasive myths treated as fact because they have utility". Just because a concept is useful does not imply that it is a real thing in our universe. This may not affect most people in their day to day lives too often, but if you want to get down to brass tacks you have to know the difference.