On April 24, 2012 many started to see that Google has started to penalize companies that are buying links for the purpose of passing off the rank. The Google Update was called Penguin. Since then, there have been several different Penguin/Panda updates rolled out by Google. SEM has, however, nothing to do with link buying and focuses on organic SEO and PPC management. As of October 20, 2014 Google has released three official revisions of their Penguin Update.
It takes skill to drive and convert traffic. If you do it yourself, it takes a significant time investment. If you outsource it, it takes a considerable monetary investment. Either way, you need resources. And you’re doing all this in a highly competitive space. Driving organic traffic is no longer just about deploying keywords. SEO is a lot more nuanced and complex than just targeting keywords. You have to consider different keyword types, the search intent of the user and the stage of awareness of your prospects. It takes time to see results.
I agree with the point that a small or medium-sized business will have limits for budget and resources in generating brand search, but I wouldn't say that stops them from potentially producing huge growth there if they do something interesting/innovative etc. I can think of quite a few small to medium sized brands that have more name recognition than larger companies in their space. The challenge is that many of those brands are led by people who are very good at generating marketing and publicity - it's harder for small brands to be able to afford to pay for a top level consultant or agency.
Although it may have changed slightly since BrightEdge published its report last year, the data still seem to hold true. Organic is simply better for delivering relevant traffic. The only channel that performs better in some capacities is paid search ads, but that is only for conversions, not overall traffic delivery (Paid Search only accounted for 10 percent of overall total traffic).