While most of the people says that social media is the great way to get more people involved in your portfolio, I have checked the social media of one of the elite artist.
100+ followers on twitter. 2 subcscribers on the YouTube. 10 000+ sales. Thats it.
So I guess the one thing which makes sense is quality/genre of material.
Nothing’s likely to beat quality, when it comes to sales, although having a decent social media present isn’t going to hurt.
That’s right. Buyers use their money on high quality items
But if your item is great enough, let’s use social media to get more visitors 
Promotion, much like financial investments, are all about diversification. The following phrases spring to mind:
“Don’t put all your eggs in one basket.”
“The whole is greater than the sum of its parts.”
In other words, social media isn’t a single contributor to success, it should just be an additional part of a much bigger promotional strategy you should employ. 
All things come into play, as @scottwills indicate. I think of social media working for AJ like this - if you can have 2 or 3 instant, incoming “external” sales of your recently uploaded item, that’s usually enough to survive in the upcoming flood of similar items coming in the next few days. And if you’re still on search page 1 after those few days, you’re bound to get the organic snowball rolling, and after that you should be fine. Given of course your item quality is stellar 