No, the chemistry hasn't changed but John's perspective on it has - dramatically. And, while the chemistry hasn't changed home brewers now have, in addition to much better knowledge, tools to let them deal with it more effectively: inexpensive pH meters and RO systems and powerful computing.
If you want to try SN's approach (treatment with phosphoric acid) the article and graph at http://wetnewf.org/pdfs/alkalinity-reduction-with.html
may help. The graph will appear (with alkalinity spelled correctly) in the new book along with others for alkalinity 50, 150 and 200 but you can roughly scale the results from the 100 ppm chart to other actual alkalinities.