Why do teleconferencing platforms require a host? [on hold]

In some teleconferencing platforms, such as WebEx and GoToMeeting, meeting attendees who arrive before the meeting host cannot be placed into conference until the arrival of the nominal host, and cannot continue speaking after the nominal host's early departure (some, like WebEx, allow that but limit it to 5 minutes).

If, for example, a regularly scheduled meeting of peers happens and the nominal host does not arrive even if everybody else does and some are both prepared and qualified to lead the meeting, the meeting cannot occur at all, at least on that platform with the published meeting ID.

These companies advertise their offerings as replacements for or analogies to in-person meetings. In real in-person meetings, some people arrive to the conference room (or if full, the hallway outside it) early, and all attendees present are free to communicate with each other prior to and regardless of the nominal host's arrival or departure.

The host requirement does not appear to be imposed by a fundamental limit of the technology; it seems companies had to go out of their way to program in strict enforcement of nominal host presence requirements.

Conferencing platforms could allow participants to join and leave a meeting as they arrive and depart regardless of the nominal host's presence. (They could also limit this to some reasonable timeframe around the scheduled time of the meeting).

These nominal host presence requirements seem to be set as default (if optional at all) by an intentional interface design choice. Why? What is the UX reasoning behind that decision? Who benefits and how?