The new system is not 'better' than the old system, and is probably significantly worse. While it's true that Welch's advice is no longer valid, it's because the legal, financial, and monetary environment has changed so much since the heydays of GE.
My grandfather retired a millionaire after working as a basic GE accountant for his entire postwar life. So as far as he was concerned, GE treated him well, and it treated his family well enough that my mother still remembers the Christmas parties that the company threw in upstate New York for their genuine human warmth.
When I compare how GE treated my grandfather versus how my father was treated by the companies that he worked for (taking the ambitious, go-getter advice), I am struck by how poorly he was served by both that and the overall cultural structure of the United States. My grandfather survived a Nazi prison camp for the US Government, and his weeks of eating grass soup paid off.
So to people saying that Welch's advice was psychopathic bullshit, I say sucks to you. Grandpa worked 9-5 for Jack, was not a particularly ambitious man, and came out way ahead in return for his loyalty. While surely this did not work for everyone, it did for enough of the people for stories like this to be common.
My perspective is entirely different -- because the US no longer rewards loyalty in either the public or private spheres. It is in fact punished, as this writer notes. How exactly can you build a company that lasts for longer than a relative eyeblink when every person is looking out for #1, and expects to be stabbed in the ass by everyone around them?
LinkedIn is a pain in the ass. Propagandizing for yourself to eke out a good living and career hopping all over the country is a pain in the ass. Both activities are tangential to producing profitable work over a long period of time. Every jackass who wants to get a VP position has to be a hot air spewing 'thought leader' now. This is all wasteful activity that defeats the entire economic purpose of firms.
The modern cynicism is corrosive to our long term prospects as a country, even if it is correct individual advice for the current environment. It will not survive, because this country will not survive as a single entity given such broken incentives and cultural mores.