Fifty years ago there weren’t any “worthless” degrees. For example, I graduated with a BA in Philosophy, answered a newspaper ad on a whim, and, lo and behold, was launched into a successful career in Information Technology. (I had never seen a computer.)
College in America no longer works the way it used to:

The Law of Supply and Demand

Two decades ago in his book, Another Way To Win, Dr. Kenneth Gray coined the term “one way to win.” He described the OWTW strategy widely followed in the US as:

• Graduate from high school.
• Matriculate at a four-year college.
• Graduate with a degree in anything.
• Become employed in a professional job.

Dr. Gray’s message to the then “academic middle” was that this was unlikely to be a successful strategy in the future. The succeeding twenty years have proven him inordinately prescient and not just for the “academic middle.”
The simple explanation is that it comes down to “supply” (1,900,000 graduates annually) and “demand” (suitable jobs).
A half century ago only seven percent of high school graduates went on to college. In post-WW II America our economy was booming while the economies of many European and Asian countries were–only slowly–being rebuilt. The “Law of Supply and Demand” strongly favored the freshly minted college graduate.
Today forty-three percent of graduates are going to find themselves underemployed.

The Quality of the Supply

Today, when forty-five percent go on to college, many of the students are marginal academically—not capable of serious, college level work. That doesn’t prevent some of them from getting a degree in some subject or another.
However, there just aren’t anywhere near enough suitable jobs for the army of graduates. College is a competition for a few good jobs, and many are going to lose.
Fifty years ago prospective employers assumed a college graduate was smart. Today college grads are a-dime-a-dozen. Employers sort through stacks of resumes, culling the “wheat from the chaff.”
A student’s major is going to be one of the key determinates of whether a resume goes into the “interview” stack or ends up in the wastebasket.

Underemployment

Skills Acquired vs Skills Required

Many college programs, courses, and curricula, and the ensuing degrees, don’t align with entry level jobs. This is one of the forces that is spawning the “New Collar” movement.

https://www.ziprecruiter.com/blog/the-best-paying-new-collar-jobs/

Ryan Craig’s book, A New U, lists over two hundred programs of a boot camp/apprenticeship nature that lead to well-paying jobs. Most of these programs do not require a bachelor’s degree to be considered for acceptance.

Return on Investment

Many years ago, my annual tuition was $360. I could pay for that by working seven weeks at minimum wage. Today tuition at a state university would require you to work six MONTHS. Tuition has gone up 200% in just the last twenty years.
My starting salary was more than twice what I paid for my entire college education. Today wages are flat. We are headed into territory where going to college to become a high school teacher (starting salary of $40,000) doesn’t make economic sense.

Summary

Let’s not call them “worthless” degrees. Let’s use Dr. Gray’s terminology and call them “anything” degrees. The reasons universities offer “anything” degrees is because they can. Parents and students are very poor consumers. They haven’t done their homework. They are financially illiterate when it comes to college. They just ASSUME “One Way to Win” still works, and the parent whips out her checkbook while the student starts applying for student loans.

Notes:
When I make this argument, the most common reaction is, “It’s not the purpose of colleges to provide vocational training. That’s beneath the dignity of the institutions of higher learning.”
To which I respond,
“I remember when the computing paradigm changed from mainframes to personal computers. Many computer companies failed because they couldn’t see “the writing on the wall.” (IBM was nearly one of them.)
Ten years ago, driven by The Great Recession of 2008, the “why go to college” survey data shifted from: learning, following a passion, and self-discovery to graduating with a degree that will lead to getting a better job.
Author Ryan Craig pronounced this watershed as ‘The Employment Imperative.’
I would just paraphrase James Carville, “It’s the jobs, stupid.”
We are LONG past the point where the average family can afford to send “little Johnny” to college to “find himself.”
The “New Collar” jobs aren’t Mike Rowe’s “welding.” When parents figure out their kid can make $100,000 a year sitting in an air conditioned office without incurring $50,000 in student loan debt, you can expect to see post-secondary education begin to undergo a sea-change.