Further to your point I think that breakdown of work is a pretty naive and incomplete take on the work of an accountable and robust review committee.
As I’ve experienced serving on a few from academia to industry to civil society; many great ideas will arrive in mediocre applications with fuzzy goals, stretched timelines and inadequate checkpoints.
Ideally it would be the role of the committee to shepherd through such applications which, depending on the scope of the work this can take weeks to months of dedicated meetings with applicants, followed by reviewing check-ins and deliverables as they occur once the project is underway. The work doesn’t stop once the grant is approved, arguably that is when the real work of the committee begins.
For example, we must also consider the work required when things don’t go to plan. Schedules fall behind, accidents happen, budgets are overrun, and worldwide pandemics undo weeks of work. Different grant applicants run into duplication of effort or conflicts of interest. Committee members need to be available to respond to requests for changes in scope, budget reallocations, project cancellations and a potential stream of requests for input and oversight.
All that work is multiplied by each project. That oversight takes time and work to do properly. It may be the case that the community prefers to leave such effort to the wider community but that, in my view, would be a mistake and one of the firm reasons I think the committee needs full time effort in some form.