From the late 1990s until five or six years ago, it was fairly easy to keep up with the latest interesting stuff in terms of full stack. Adjustments were modest year to year. At this point I've entirely given up trying to keep up with the very rapid fad switching that has been going on. Real full stack is now only possible if you freeze pretty strictly across the stack and don't try to keep up as the next fad rolls in for a given part of the stack. If you try to keep up with all the fads now, it'll burn you out (and most likely make you hate what you do as you realize how pointless the constant switching is).
I've found - as you'd expect - that abandoning the stack rat race hasn't had any negative impact. Most of the latest fads are entirely unnecessary and bring nothing to the table that prior numerous solutions didn't already deliver toward building, launching and maintaining product.
But padding resumes is one of those seemingly fundamental problems of any industry (or bureaucracy). Many poor decisions by (middle) management come down to padding resumes - when the consequences of bad decisions eventually happen said managers are gone. Hell, you could even argue that a lot of higher education is about padding your resume rather than learning skills. Unfortunately, it seems that we have to live with the added baggage of "padding resumes".
Technology jumping based on anecdotal evidence of the efficacy of doing so. Jumping around so often precludes a lot of practitioners from gaining a deep experience and understanding with the tools they're working with. This may be the only industry I know where pertinent knowledge and experience matters little.
The notion of "Full Stack Developers" gives the impression that one can be proficient top to bottom. What I find interesting about the label is full seems to usually be bounded on the lower end at a place much higher than a place where I would use the term full. This is one of the many areas in our industry where hubris is in play. Specialization is usually preferable for quality and scaling.
Real world business continually drives the fast and cheap legs of the stool to be chosen by management. However, I think this grates against most practitioners who not only care about quality but would admit, the aspect of quality is one of the major reasons they are even in the field to begin with. There is a large natural tension at play here. I think it's this tension that Joe was articulating.
It's seems to me the most satisfied folks in this field are the ones fortunate enough to be compensated for working within a bounded context where over time they can gain more and more experience and knowledge. This naturally leads to a growing confidence and a sense of control over the context with which they work.