> Is it that social media is worse, or that returns on advertising for local businesses have always been bad but only when we could track them have we noticed?

IMHO the latter. Returns were and are always terrible, with occasional "home runs" that then get parroted by every marketing guru as an example of how powerful social marketing campaigns can be. But of course, your plumbing business, or accounting firm doesn't have the same business model, market or customers as said example.

My point is that social media is no worse, or better than traditional marketing, it's just that, we can prove it's terrible with data. Of course, if everything is "terrible" ... none of it is.