While it is kinda unfortunate to have one unbalanced test suite as the major external progress indicator, there are.. like no other good options that don't involve someone manually going through like the top 1000 sites or something and checking whether they look good. That leaves having no progress indication whatsoever, which is also pretty bad.

And, in any case, implementing more of the standards is just simply good, and would need to be done at some point anyway.