Speaking as a sound engineer, that's a bit like saying you can paint a masterpiece for the price of some brushes, tubes of paint, and a bit of canvas. It takes a large investment of time (which has a significant opportunity cost) to become skilled in this area. Many excellent musicians are poor or mediocre engineers, and vice versa. The cheaper and more ubiquitous recorded music is, the higher consumer expectations are: a late-night jam recorded in a hotel room or a rough-edged recording of a live show won't get the time of day from most people. The shortest route to a breakthrough these days is to be pretty and make a Youtube video, but that too is easier said than done.
In addition to the basic ability to play music and perseverance, artists have usually needed an extra something special to break out. Whether it's exceptional songwriting, virtuoso guitar playing, or a truly gifted singing voice, or it's having a unique, marketable personal fashion style, contacts in the music industry, or fame from some other endeavor, having some way of differentiating yourself from other aspiring artists can make all the difference in the world.
Possessing gifted production skills (or knowing someone who does who will help you produce your music) is just another edge some artists may be able to bring to the table. Then again, if you are merely a mediocre engineer but a truly gifted songwriter or guitar player, those mediocre skills may be enough to let people discover your other, more remarkable talents.
