Committees work on averages and “most votes win.”
Therefore, in a committee people (over time) are hesitant to speak their mind, outliers are outvoted, and passionate singular voices have no impact and thus are rarely heard.
Committees can be great when it comes time for group discussions and decisions such as where to put the new water cooler, or where to have the company picnic.
But beyond that, dynamic organizations become dynamic though singular ideas, passionate reasoning, and risk taking, all of which a committee stifles.