Earlier quoted context omitted.
Middle-Earth most definitely is not based on Europe and claiming such is unsupportable. The geography and map of Middle-Earth is absolutely nothing like Europe, no similarities whatsoever, and no geological process known could make it similar. On the other hand, Middle-Earth is strikingly similar to a mirror image of North America.
I didn't say based IN I said based ON. Those are similar sounding but completely different. The former implies it's actually based in the same country and lands as Europe. Whereas the later implies it's merely inspired by to some degree.
Not for nothing, Europe is a continent. Whether you believe Tolkien based his works on or in Europe, both are false on their face. It doesn't even make sense, so please try to better articulate what you mean. Because you literally have argued that Tolkien based the continent of Middle-Earth on the continent of Europe, then you have waffled and changed your argument from in to on. Either way is nonsense. What you must have meant was Tolkien based his stories, not the element of his story setting, Middle-Earth, but the stories themselves, on history and mythology of the various peoples of Europe.
But, in fact, other than Scandinavian epics and myths, and specifically Finnish and Norse epics and myths, that is false.
If you can support your claim, you'd be more convincing. An example of some very similar non-Scandinavian European story found in Tolkien's work would drive your point home. But I am unaware of any example of, say, Italian or Romanian or Polish or Swiss or Danish folk stories or myths being borrowed by Tolkien. And we need not be so vague. Europe was never a single culture, but always many. And Tolkien was not writing to give Europe a history and mythology; that purpose was only for England.