> Viruses are not so complex that we would trivially overlook a feature that would literally change the phylogenetic classification in a dramatic way.

You might think that, but in the past two decades theres been so many "how did we miss that?" in so many fields. I'll let field experts bring specifics up- I only know popularized examples like Roman Concrete. And the ever-easy Mars unit-conversion error.

You can speculate if you like, but the claim you're advancing is fantastical to anyone who has studied virology, and requires an accordingly fantastic level of supporting evidence.