How is the 100% needed to start the beta determined? As the total of reputation of the committed users until a goal number Is reached? Or do we need a certain number of committed users (this is what I thought was the case).
Moreover, I just read you've previously failed to get this same proposal progress to the beta phase. Is there a fixed time interval to score this 100% maybe?
User with more experience (reputation) are weighted heavier towards the commitment score. So it's a combination of how many people commit and how much experience they have on the network. I don't believe the actual algorithm is public, but every commitment helps move that needle.
Proposals can fail to launch if it has absolutely no activity at all for a full month or more (abandoned), or if it takes longer than two years to launch. It's been demonstrated that proposals taking more than two years do not have sufficient momentum to launch a successful site.