Even with leaders appointed to guide them, the spiritual decline of the Israelites could not be stopped. God's efforts to rescue the nation ultimately proved ineffective against their stubbornness [מצודת דוד]. The situation deteriorated to the point where the people often refused to listen to their judges even while those leaders were still alive. As a result, enemies were able to overpower the Israelites during the very lifetimes of the leaders meant to save them [מלבי״ם].
The root of this massive failure was not just the act of idol worship itself, but rather a deeper issue of deaf ears. The entire process of returning to God depends on a willingness to listen, as a person's spiritual healing always begins by opening themselves to correction. When people disrespect their spiritual leaders, they block any possibility of moral recovery. In this case, the Israelites' intense attraction to idol worship prevented them from taking even the basic first step of paying attention to their judges [אלשיך].
This abandonment of the proper path did not happen slowly or in stages. Instead, the nation turned away all at once, with sudden and complete speed [מצודת דוד]. In doing so, they completely abandoned the path walked by their ancestors, such as the generation of Joshua and the elders. That earlier generation was defined by a constant readiness to listen to their prophets and judges. They accepted moral correction with quiet humility, just as they had done when corrected by Moses [מלבי״ם, אלשיך]. By refusing to follow this ancestral tradition of listening, the direct consequence was that the Israelites failed to actively practice God's commandments, acting in total opposition to the legacy of their forefathers [מצודת דוד, אלשיך].