People will buy the justification as long as their lives are stable or even better, improving. That's stalling now.

An ideology's legitimacy stems from its perceived ability to handle crisis. Liberalism isn't doing that well anymore so it is beginning to lose credibility. Since it has no answers, it can only cling to legitimacy by silencing its critics, violating its own stated principles in the process and thus getting stuck in a feedback loop of a credibility death spiral.