The following paragraph was included in the full research bulletin on our web site www.icinsights.com and explains why we include the foundries in the ranking. It was not included in this eetimes excerpt.
"The top-20 ranking includes three pure-play foundries (TSMC, GlobalFoundries, and UMC) and four fabless companies. IC foundries are included in the top-20 semiconductor supplier ranking because IC Insights has always viewed the ranking as a top supplier list, not as a marketshare ranking, and realizes that in some cases semiconductor sales are double counted. With many of our clients being vendors to the semiconductor industry (supplying equipment, chemicals, gases, etc.), excluding large IC manufacturers like the foundries would leave significant "holes" in the list of top semiconductor suppliers. Overall, the ranking provides a guideline to identify which companies are the leading semiconductor suppliers, whether they are IDMs, fabless companies, or foundries."
"The list of top 20 worldwide semiconductor companies (including producers of ICs, discrete, optoelectronic, and sensor chips) for the first half of 2013 include three pure-play foundries (TSMC, GlobalFoundries, and UMC) and four fabless companies."
It looks like you are counting twice. The foundries are producing the chips the fabless companies are selling.
With mobile on the upswing, and PCs on decline, it seems like a fair bet that these trends will continue for the immediate future. It's also possible that some players will choose to leave the market to focus on other areas.