I don’t disagree. Different parties have different makeups. Dems are big tent and Repubs are unified single issue voters.
They stopped trying to be “big tent” when they started courting Republicans instead of their own voting bases.
What policies changed when they courted Republicans? Because as far as I can tell nothing changed for that but they did say that even with our policy differences, Republicans advocated voting for Dems. Dems have lgbtq+ and black people and immigrants and unions and many other groups that don’t have a single unifying cause. Republicans have Christian white people for the most part.