This is very much debatable. Only around one in four English words is Germanic in origin, whereas half of English words are Latinic or Romanic. [1]
Some properties of English's grammar are also more similar to Romance languages than Germanic ones. For example, whereas Germanic languages only mark tense on verbs, English verbs (like Spanish verbs) are marked with aspect in addition to tense: there is a distinction between "I played tennis"/"I have played tennis"/"I was playing tennis".
I'm not saying English is a Romance language. But it's a much more interesting problem to figure out why it's not considered a Romance language than you imply.
Some properties of English's grammar are also more similar to Romance languages than Germanic ones. For example, whereas Germanic languages only mark tense on verbs, English verbs (like Spanish verbs) are marked with aspect in addition to tense: there is a distinction between "I played tennis"/"I have played tennis"/"I was playing tennis".
I'm not saying English is a Romance language. But it's a much more interesting problem to figure out why it's not considered a Romance language than you imply.
[1]: https://en.wikipedia.org/wiki/Latin_influence_in_English