Successful advertising doesn't manifest because of the advertising medium you choose (Radio, TV, Billboard, Digital, etc.). It's all about your ads.
Think about it. What if you wanted to run a Radio ad, but your ad talked about how to make the perfect pot of coffee and nothing about your business? That's obviously not going to bring you any new customers.
It's the same thing when your advertising message (your commercial / ad) doesn't shine a very pleasing or persuasive light on your business. When the ad message and ad strategy stinks, then your ROI stinks.
Most advertising mediums can work to some degree as long as it as an "audience". Radio, Television, Online, Newspaper, Billboards, bus benches, sandwich boards, etc. are just a place to get the word out there about your business. You're basically just renting an audience.
Yes, most options CAN work, but rarely do... because of the poor ad writing, poor strategy, no thought put into it, no research on competition, and poor research on your current customers.
When you hire LMC for your advertising... before we even consider deciding WHERE to advertise, we're going to talk about WHAT to advertise. Meaning, we'll talk about your overall branding, your goals, your competition, etc., in order to figure out the best things to say to your potential, new, profitable customers.