The idea that people are being forced out of inherently fulfilling object-manufacturing jobs into inherently unsatisfying service jobs isn't particularly true, and even if it were, that's not what alienation means. While many service jobs suck in ways Marx can be applied to, mass production was the original alienating job.
It's the lack of agency that's alienating, not the transitory nature of the produced work, or even the job being inherently pointless (people cheerfully do non-productive things all day)
The part about specialization is questionable as well. While there's not much use for a casual architect, the modern, deep-specialization economy means it's impossible to hire if you limit your search to people who made the life decision at 12 that they wanted to be an packaging technology specialist.
This creates a system where it is not just acceptable but expected that individuals will have various careers throughout life: What we do for a living can't be a fundamental characteristic of our identity if it isn't what we were doing a decade ago and isn't what we're likely to be doing a decade from now.
This is kind of a problem for the article author's defense of Marx because it's the alienating, interchangeable nature of 21st century work that allows the individual to increasingly have an existence outside of their job. Just look at all the weirdos over at tumblr: many of these people have jobs that are so non-identifying that they have to get together and brainstorm new identities to label themselves with.