Interpretation of phylogenetic tree

[HELISA]

I have an example of phylogenetic tree which depicts genetic relationships between the serotypes of RNA virus based on comparison of the sequence of part of the capsid-coding region of the genome.
This dendrogram could be intrepreted as a historical fact and a hypothesis., which I just got to know from my previous discussion on the forum.
This tree considered as a depiction of historical fact provides information about the percentage difference in nucleotide sequence of different serotypes of the virus and that is all what I can consider as a fact, right?
On the other hand, if this dendrogram is interpreted as a hypothesis, one may suggest that the high mutation rate observed within capsid-coding region is due to its relevant role in determining the virus host range, or it could be concluded that different mutation pattern in viral genome might occur in response to host evolution which originate from different regions. As far as i know there could be many different ways of hypothetical interpretation of such phylogenetic tree.
Do you have any other ideas about different interpretation of this tree?