It was one of the hallmarks of the progressive era. It is a breakdown because it gave the Federal government more power than what the original framers intended. Just because something changed doesn't mean it's for the better. Ask Coke how that change worked for them.The common refrain from some conservatives that “We’re a Republic, Not a Democracy.” It's nonsense. We're both.
The 17th amendment was ratified by 41 states and only rejected by 1. Hardly a left wing plot.
And despite your reticence to change, our system of government as described in the constitution, includes the ability to change and adapt the system over time. It isn't a "breakdown" to change the system. It's working as intended.