Thank you so much! Very nice to see that ISO was convinced to once again follow the promise (to Adobe) of no-cost access to the PDF standard that they kept until PDF 1.7 but broke with PDF 2.0.
However, TFA is not about PDF, it is about a profile called PDF/UA-2 aka ISO 14289-2. That one is $223 from the PDF Association[1] or 173 CHF from the ISO[2].
It's very early days for clients. I guess the support is not really there yet. However most publishers and eprint archives have settles on pdfs rather than html annoyingly, so this is one of our best hopes of accessibility for academic publications.