nice article. Not very surprisingly in the result (”Content is king”), however interesting to do the maths (salary of SEO Manager vs. AdWord campaign).

Pls allow some remarks:
1) SEM is usually understood as Search Engine Marketing (http://en.wikipedia.org/wiki/SEM) which would include SEO and AdWords (among others). At least in Germany SEM nowadays is a synonym for buying traffic via AdWords. However, it does not change your analysis much.
2) PPC is also the model behind AdWords – you pay (Google) per click they provide you. For me is “SEM/PPC/AdWords/Analytics” therefor like saying the same thing three times: Buy traffic at Google (and measure it through Analytics). Still, it does not change your analysis much.

BUT:

3) Your experience and article refers to a e-Commerce site. Have a look at a newssite for instance. There running a keyword campaign is much more work, it changes daily, sometimes even within minutes (e.g. breaking news). The SEO-guy should provide the editors with the right keywords, make the analysis the editors can not do because they have to write an article – and do it FAST. Additionally, the result (traffic/views) of each article should be measured – does this lead article perform as good as the benchmark? This can not be done with Google Analytics, you need a real-time webtracking tool. Additionally, as the monetization of such a website is mostly depending on (reach based) CPM-advertising, the calculation of the “break-even”-point of Adwords is not that easy like in e-Commerce.

Okay, to sum it up: I agree, that there are a lot of “SEO experts”, “SEO Manager” etc which are not worth the money they request. However, for content driven sites I believe there should be someone taking care for Keywords, AdWords, and SEO-results. If this person is worth 35.000 GBP/year… I don’t know :-)