An interesting fable that illustrates the value gained through experience. The expected / known problems can typically be outsourced and solved by anyone with the troubleshooting guide. The unexpected problems are the ones that require ingenuity and deep expertise. The same thing applies in medicine. 95% of the time any surgeon may be able to perform a procedure; it is the 5% of the time that something goes wrong that the expert can save your life.
Methinks a company needs both the old and the new. A synergistic design environment between a sharp young one with ideas and an experienced troubleshooter can only lead to a win-win situation for that company.
This not only applies to SoC design, but also to any of the design activities. It is not always possible to hire people thinking about all different technological expertise in mind. Hence sometimes it is worth seeking the source of expertise outside, which most of the time gets available cheaper.
The tools are what make it humanly possible to make very large numbers of transistors all do the right things at the right time, but the tools hardly do all of the work!
To the author's point about right-sourcing a design team, the most successful SoC projects do include some senior, very experienced designers, as well as younger junior designers.
As for being insulated from the actual circuitry, it depends on which level of he design flow you're talking about. One of the great things about the evolution of EDA is that it spans all the way from the very physical -- DRC & LVS to replace the "light table" you mentioned -- up to electronic system level (ESL) tools that allow system engineers to explore algorithm trade-offs and hardware vs. software design partitioning.
Large IDMs can and do have all of those different skill sets in-house, but smaller companies may be lacking some of those skills at one end of the spectrum or the other -- thus the author's pitch for the services his company provides.
When I started in this industry, EDA was a light table in the corner of the room. The chips today are much more complicated, but the engineers are insolated from the actual circuitry by tools that do all of the work for them. This causes more time to debug any issues.