> Only around one in four English words is Germanic in origin

That's the % in the dictionary. More than half of Japanese vocabulary in the dictionary is based on Chinese but no one argues Japanese is a Chinese creole. I forget by whom but it was once pointed out to me that in some genres - ranging from drinking songs to nursery rhymes - the words that come from Old English often make up more than 90% of the words. Similarly, if you sample the dialog in a kitchen or office while people gossip the ratio is also going to skew heavily like 70 - 80% Germanic. (Japanese shows a similar effect with all its Chinese vocabulary.)

Indeed, it's not tricky to write about everyday grounded things with nothing but straight Anglo-Saxon roots. (I've been doing it so far this whole paragraph -- oh that's Greek.) Difficult to achieve similar results utilizing exclusively Latinate vocabulary.

Of course, a history book or engineering manual will be different, and Graeco-Latin vocabulary might well be in the majority there.