What they did
Ahrefs took roughly 14 billion pages from its Content Explorer index and estimated each page's organic traffic by matching ranked keywords against a database of about 651 million keywords.
What they found
96.55% of pages got zero organic traffic from Google, and a further 1.94% got between one and ten visits a month. In other words the vast majority of published pages never pull search traffic.
How much weight to give it
This describes an outcome, it does not explain a mechanism. It tells you most pages fail to rank, but the study itself cannot prove why any individual page does or does not. Ahrefs' own reasons, thin backlinks and intent mismatch, are plausible correlations rather than tested causes.
What it doesn't prove
Traffic is modelled, not measured, so pages living entirely off rare long-tail queries are undercounted and the true share with zero traffic could be lower. The index also favours quality content, which is not the whole web.