Why are so many companies demanding nothing but engineers? Really they are not the only college majors in the world?

There is a lot of demand for engineers because everything from games to refrigerators to cars is using technology. That noted, there are thousands of companies that do not recruit on campus or at job fairs. There are millions of jobs for college-educated people who are not STEM graduates. You just have to find them yourself.

Almost all job demand right now is for educated, trained specialists who can step right into a job & accomplish something. Certainly the world needs authors & artists, pathologists & plumbers, etc. But right now, companies are only investing the great deal of time & money (often several thousand dollars) required to attend job fairs, campuses, etc. for recruiting on recruiting engineers, regardless of other openings, other needs.

You need to determine what you can actually DO for an employer that's worth paying for; research prospective employers who could use those skills, abilities, etc.; prepare yourself properly for job searching (writing a resume to current employer standards, interviewing skills, attire, etc.); and actually get out there & look for job. Attending job fairs or going through your university's Placement Office is nowhere near enough effort to find a job, especially when you have no explicit training & expertise in a specific occupation.

They are looking fir people with technical knowledge that can do math above the basic arihmatic level with a calculator. Most engineers have no idea how to clone anything. Engineering is NOT major. It is a bunch if degree program. Engineering and physics are applied math in real world problems.

to be able to communicate with other engineers and scientists. At least one university requires all engineering students to take an English technical writing class.

There are many different types of engineers out there. The reason so many companies ask for engineers is because engineers go to college for around 4 years to learn how to build, design, and maintain engines, machines, and public works. Getting a degree in humanities is like getting a degree in trimming your finger nails, everyone has the common sense for it and the degree is useless.