Because "all of us", collectively, is usually stupider than "any of us". It's hard to beat small focus'd tactical teams. Large committees get bogged down.

Even way back when there were few commercial incumbent interests in web standards a the W3C or IETF being this way or the other, and the groups were small, focused and collegial, it took a fair amount of patient doing to achieve outcomes. For something more global and "significant" -- getting the respective rep teams of 10-large banks to agree on technical standards for money transfer -- oh, boy....