[__d]

Many standards groups require payment for their published standards: the ISO and most national standards bodies (ANSI, etc) are maybe the most prominent examples.

This is their business model. You pay for access to the standards documents, and that money funds the development and maintenance process. It's supported by governments requiring adherence to these standards, so implementors are obliged to purchase them.

Gratis access to standards is a newer model which relies on a different funding stream. The IETF is one such example.