I would not say that was correct. Almost all people (including posters on this thread) know that we have left the EU and the transition period has ended, and accept that. The debate is about the impact of Brexit on this and (to a lesser extent) other countries after we have left. As @najaB has inferred this will take some time to play out. To follow up your example, it is not what effect 'winning' or 'losing' World War II had on a single soldier but on Japan as a country (as well as Germany, UK, USSR, other countries). This is quite a large scale example but there is also the effect on the US of their civil war; on much of Europe of the fall of the Berlin Wall; on southern Africa of the end of apartheid; the 2004 tsunami on south east Asia; the financial crisis of 2007/8 virtually worldwide; and others going back in history. All these had a long term impact or, in some cases, are still having an impact. There is no reason to believe that Brexit won't have an impact on the UK and other countries, if it didn't there would be no point in having done it, and that the after effects will be felt for some time, some will have been anticipated, some won't. As an example of the latter, the election of Joe Biden (less anti-EU than Donald Trump); when we voted, Trump was a candidate and Biden had backed Hillary Clinton.I went back 61 pages to page 1 started on 10 Nov 2020 and this is the second Brexit thread. So we had already left the EU.
This is like the old Japanese soldier fighting on thinking the war is still going on. I'll stick to the railway threads as this is a waste of effort.
Short of the intervention of the Mods, this thread potentially has a lot of material still to cover and has the potential to be a Forum James Anderson.