Why don't Christians realize that the geneologies in Matthew and Luke show that Jesus is NOT the messiah?

The geneology in Matthew shows Joseph's line, but Jesus isn't Joseph's son, so Joseph's ancestry is irrelevant. Luke shows Joseph's again, but many Christians think that it's really Mary's geneology. Even if it were Mary's the ancestral line stems from Nathan, son of David. The messiah is said to descended from David's son, Solomon, not Nathan. descend*