Although it is not necessary to have a college degree to become a writer, great writing and editing skills are imperative. In any realm of writing that you chose to pursue, college classes can definitely aid you in developing the skills which could give you a competitive edge. You can be very skilled with words but errors and poor grammar can distract from your work. When you are a writer you are not just a writer! You have to be an editor, a critic, and a skilled researcher.
There are some jobs in writing where the employer may specify that you meet the criteria put forth by the company. That is just dependent on what type of job you are trying to obtain. If you apply for the same position as another writer who has a degree in journalism you will be the least likely candidate to get the position. If you chose to apply with a company you need to be prepared to prove that you are a qualified candidate. In many cases you have to start at the bottom and work your way up. This means taking whatever jobs you can even if they pay little to nothing just to build up your resume.
If you chose to pursue this career without going to college you must have the drive and self-discipline to educate yourself. You need to learn the process of marketing yourself as a writer in whichever genre of writing you chose to pursue. You have to write query letters and come up with original ideas. Sometimes you have to write about subjects that do not particularly interest you. You may not know anything about the subject at all. That is where the research part comes in. You might spend more time researching then actually writing the article.
Creative writing is a whole new career within itself. If you want to write books or poetry you need to research the market first. There is a very small market for poetry,is largely funded by other poets in the form of contests. It may seem crazy to pay a fee in hopes of making money later but as a poet, it is a reality that you are going to have to deal with. It is common knowledge that published authors have taken large amounts of time out of their lives to invest in their work. You will get turned down many times before you find the right publisher to sell your work to. There are other options such as self-publishing which once again is an investment. Creative writing classes would definitely be beneficial. Many of them are taught by published authors who can give you great advice on getting started and ways to motivate yourself.
Is a college education necessary to become a writer? No, it is not necessary. Is it helpful? Yes, it is very helpful. If this is the path you chose, you have to be willing to stop along the way and do the labor to move all of the obstacles so you can reach your desired destination. An education is like having a machete to help you clear it. It is not necessary but it definitely helps!