You've stepped into a world that is over-saturated, convoluted, and highly competitive. A quick google search for "buy beats on-line" will show you that. Your consumers are both fickle as hell, opinionated, and in some cases lack focus and direction. Your consumers want to get everything you have to offer for free and even if they did want to pay for it, they usually won't because they either have no money or would rather spend it on more important things like weed, shoes, gear, jewelry, hoes, partying, the turn up, ect.
This is not a thing for the faint of heart to get into. If you're not into taking a deep dive into on-line business marketing, becoming a novice website designer, being a promoter on social networks and lastly, willing to pour your heart and soul into your music then you did the right thing by quitting to make room for the people that are.
I know that sounds harsh and I truly mean no disrespect but I'm telling you like it was once told to me. When you choose this life, you're choosing to attempt to sell a product to the most difficult audience to sell something to because there is an over abundance of it. The minute you stop trying to sell music and instead build and sell a highly demanded brand, is the minute you'll start making money. I've made sells on Soundgine and I just got started a few months back. The truth is, it is possible but it's a tough grind. It's a day by day hustle, I'm constantly learning new marketing tactics and trying different things out to see what works. I'm analyzing the traffic trends on my website, and seeing how I can benefit artists by offering more than just beats for sell. Like Oxygen Beats mentioned, many of us get repeat business from artists that we built relationships with. We've learned to develop the know, like, and trust factors and use them to our advantage.
I'd rather have 10 artist that buy beats and services from me consistently than I would 100 artists who'd buy from me once. You have to be creative with your offerings and figure out other revenue streams that might not actually involve selling your beats like mixing, mastering, graphics, promotion services, authoring e-books, doing tutorial videos, selling mech, ect. You can make a living off of music just realize that doesn't always mean just selling beats. I'm sure the guys that are making sells on here and attest to this.
Peace bro, good luck.