Admittedly, it has been many years since I too read Max Weber's, "The Protestant Ethic and the Spirit of Capitalism".
Although I do not have the exact date of its original publication-(if my memory is correct, it was around the first decade of the 20th century, approximately 110 years ago), Max Weber wrote an important sociological work that was very much for his time. Even though Weber was attempting to justify or validate the nexus between centuries old Protestantism and Capitalism-(or really the correlation between the centuries old Protestant ethos and the Capitalist system), he was still writing within his contemporary cultural framework-(and when looking at Weber's time, he may have been quite accurate in his description). Protestant countries, such as The Netherlands, Britain-(both England and Scotland) and even the United States-(which during Weber's time, was still a predominantly Protestant country), were either historic or burgeoning Capitalist economies who helped found the Modern Corporation, as well as having planted the seeds of the Industrial Revolution, thus underscoring and validating Weber's thesis.
However, in Germany's case, it is a bit more complex and paradoxcial, due to the fact that a sizable percentage of Germany is Roman Catholic-(especially in Bavaria, as well as the Western Rhineland, to some extent). Yet, Germany was also the historic birthplace of Protestantism-(specifically, in Northern Germany) and much of Northern and Central Germany is Lutheran. So the German historic example may have limited Max Weber's thesis.
I won't necessarily say that Weber's "Protestant Ethic and the Spirit of Capitalism" is an anachronism, though I would suggest that Weber's famed work, was very much of and for his time. The reason, is that Capitalism, since Weber's passing, has morphed into a Global phenomena and continues to expand. The Hong Kong, Singapore, Kuala Lampur, Tokyo and Dubai skylines rival the Frankfurt, Berlin, London and even the NYC skylines, thus proving, through time and Globalization, that what began in mostly Protestant lands, has successfully evolved into parts of the world that are not even religiously Christian. Therefore, the old "Protestant ethic", is reaching beyond The North European Protestant economic horizon.
Overall, Max Weber's, "The Protestant Ethic and the Spirit of Capitalism" is a Landmark work in the History of Sociology and Culture, though it is largely confined to his time.