The "it was just this back then" is rather pointless of a reason, since thing if they dont want to constant blantant copies of the previous, they change over time in newer reimaginings.
Also reasons for its inclusion into the story can be found. The openness for an EU need to exist for that...unless you want for your universe to have an exact limit right of the back. The limit can still work fine. Its just if you want to exand beyond a certain point, expect to have a basis for expansion otherwise everything you add afterwards would feel forced.
Again, "the if it cant work like this, it wont work like this" is also false since these things are not fully conected in a way to limit or effect the other in a way you expressed. There are numerous examples, even in Lego, when something didnt work in set or phisical form, but worked in the story media and vice a versa.