> Max Weber called the Protestant work ethic
...hmm. Not sure that this is quite state-of-the art in sociology today. Crediting a particular strand of a particular religion as the locus of a virtue that confers a clear fitness advantage in and of itself, and without recourse to any outside explanation, seems a bit off.
(IANA scholar, but I play one on the internet.)
No, Weber is not the current state-of-the-art, but you can see how was a bit suspicious (given the evidence that Weber was working with) that the Reformation and the first meaningful economic growth possibly ever (the "Great Divergence") in history seem to have started at approximately the same time and in the same places (England, parts of the Holy Roman Empire, Holland).
We now have scholarship based on earlier evidence (it turns out that availability of the printing press massively increased the surviving sources we have about "early modern" Europe versus the earlier manuscript-driven ages, so our sources have a distinct bias toward the post-Gutenberg world -- and the printing press itself is probably a major node in the web of causes and effects that drive this transition!) and AIUI the best current guess is that the Black Death is what initially kickstarted economic growth (the "Little Divergence"), possibly by effectively ending serfdom in those places as agricultural labor become much dearer than before the plague. The Reformation, under this view of things, is more of a consequence of economic growth -- the ranks of increasingly numerous rich-and-influential commoners and burghers asserting their place in a social order defined by the Roman church -- rather than a cause of it.
Considering Weber was publishing give or take a century ago, it not being state of the art isn't surprising. It's still influential because it established a lot of the tools used by modern sociologists, as well as providing a counterpoint to Marxist thought. Personally I'm mostly indifferent to the claim.
You're also misreading the claim, the Protestant work ethic is not claiming any virtue on anyone's behalf. Weber's claim is making a casual connection between the development of capitalism and religious covenant. It's certainly not the prescriptive theory you're making it out to be.
Well of course Weber isn't exactly state-of-the-art sociology, but when people say "the Protestant work ethic" that is basically one widely-accepted name (a pointer if you will) to an idea that sociologists have long recognized is present in some segments of many societies.