First, a bit of history. The U.S. Constitution was ratified in 1788 and superseded the Articles of Confederation. The first ten Amendments, ratified in 1791 (rather quickly after the initial drafting and adoption of the main document — oops, forgot these obvious assumptions), are known as the Bill of Rights. The final amendment to date, the 27th Amendment, though proposed in 1789 along with others, was not ratified until 1992. A half dozen additional amendments approved by Congress have not yet been ratified, and a large number of other unapproved amendments have been proposed.
The received wisdom is that, by virtue of its lengthy service as the supreme law of the land, the U.S. Constitution has become sacrosanct and invulnerable to significant criticism and further amendment. That wisdom has begun to be questioned actively as a result of (at least) two factors: (1) recognition that the Federal government serves the common good and citizenry rather poorly, having become corrupt and dysfunctional, and (2) the Electoral College, an anachronism from the Revolutionary Era that skews voting power away from cities, handed two recent presidential elections to candidates who failed to win the popular vote yet won in the Electoral College. For a numerical analysis of how electoral politics is gamed to subvert public opinion, resulting in more government seats held by Republicans than voting (expressing the will of the people) would indicate, see this article by the Brookings Institute.
These are issues of political philosophy and ongoing public debate, spurred by dissatisfaction over periodic Federal shutdowns, power struggles between the executive and legislative branches that are tantamount to holding each other hostage, and income inequality that pools wealth and power in the hands of ever fewer people. The judicial branch (especially the U.S. Supreme Court) is also a significant point of contention; its newly appointed members are increasingly right wing but have not (yet) taken openly activist roles (e.g., reversing Roe v. Wade). As philosophy, questioning the wisdom of the U.S. Constitution requires considerable knowledge of history and comparative government to undertake with equanimity (as opposed to emotionalism). I don’t possess such expert knowledge but will observe that the U.S. is an outlier among nations in relying on a centuries-old constitution, which may not have been the expectation or intent of the drafters.
It might be too strong to suggest just yet that the public feels betrayed by its institutions. Better to say that, for instance, the U.S. Constitution is now regarded as a flawed document — not for its day (with limited Federal powers) but for the needs of today (where the Federal apparatus, including the giant military, has grown into a leviathan). This would explain renewed interest in direct democracy (as opposed to representative government), flirtations with socialism (expanded over the blended system we already have), and open calls for revolution to remove a de facto corporatocracy. Whether the U.S. Constitution can or should survive these challenges is the question.
Update
Seems I was roughly half a year early. Harper’s Magazine has as its feature article for the October 2019 issue a serendipitous article: “Constitution in Crisis” (not behind a paywall, I believe). The cover of the issue, however, poses a more provocative question: “Do We Need the Constitution?” Decide for yourself, I suppose, if you’re aligned with the revolutionary spirit.