One thing to remember is that a lot of streetcar companies were started by developers who wanted to make their developments convenient travel from downtown. Many of them would have needed to consolidate or shift to remain financially viable.

The thing which killed transit was the massive subsidies for private car ownership and especially coding transit riders as poor/black. Cities didn’t kill transit because they loved traffic, it happened because much of the tax base moved out to the suburbs and generations of city planners prioritized private car travel over transit at almost every turn.