I understand the point the article is trying to make -- Where are the results? I was promised if I engage in social media, I'll be successful. Where's my pot of gold?
Marketing and advertising are the means to gain awareness of you, your brand or your product. Yes, opinions are made on marketing alone but it's highly unlikely that just marketing and advertising close sales. That's the job of your website, sales people, store, phone reps, sales process.
You can have an incredible campaign (social media or otherwise) that drives traffic and grows awareness but if you can't seal the deal, you're out of business. If you're using social media or email marketing get traffic from them, be sure to measure your results. What percentage of visitors are converting into customers?
What can you do to increase this rate? Look closely at your product, sales process, website, follow through. What can be improved? How do you share your benefit and value? Could your website landing page use some optimization? Does your online form look unwieldy? Are leads getting followed up on quickly enough.
If your traffic is growing but your sales aren't, don't shoot the marketing medium. Look in the mirror and see how you can take advantage of your traffic win.
How are you taking advantage of your social media marketing?