There is usually more to a "PhD by publication" than just publishing any 3 articles and then submitting them for the degree.

A nice 2011 article in Times Higher Education describes what the process actually requires, at least in the UK most importantly, coherence: the articles must be on related themes, and additional supporting documentation on the order of 10k words is usually required to convert the independent publications into some kind of coherent package that, very often resembles a conventional thesis.

It's also informative to look over the recent discussion on the Thesis Whisperer blog - lots of comments from people in various disciplines about the realities of publication-based theses.... and usually they describe them as more work than a conventional thesis.

For published papers like the one described by Gary King - it may be hard to write a combination of them that meets an institution's criterion for PhD by publication. Not just the coherence part but usually there is a requirement that a PhD makes a novel contribution to the field -- and it is hard to justify this with strictly replication-based approaches.

However, if the work follows King's suggestion to replicate and then make minimal changes ("make one improvement, or the smallest number of improvements possible to produce new results, and show the results so that we can attribute specific changes in substantive conclusions to particular methodological changes" - King p.120) - a series of such publications on closely related themes starts to look a lot like a conventional PhD..... although getting a paper through peer review is still quite a challenge. King's paper (and supplemental comments) can also be a useful guide for researchers outside academia to get published.