Earlier quoted context omitted.
I'd argue that's more of a symptom of the rise of identity politics in particular than the two-party system. Policy and political discourse is driven so heavily by identity today that political parties find it easier to coalesce around groups of unrelated issues in order to find their voting base. But I do agree with you in that it's an issue.
The two party system is a big factor because it allows the two parties to stay closely within their positions and voters have nowhere else to go. When I compare this to Germany there the traditional two big parties received a rude wake up call because suddenly the greens and the AFD started rising. So these parties have to refresh themselves unless they want to become irrelevant. In the US there is no such pressure.
That does not square with the US electing donald trump.