I think having TCR is contradictory to having a “a single consolidated calendar” because TCR is selective and any events which are rejected to be on the list are more likely to create their own event calendar. If your main goal is to create “one single place”, then better to scrape all events (which EthereumJesus did during DevCon4 https://twitter.com/bneiluj/status/1052191727593771008.
Interestingly, DevCon5 already have 2 event calendars https://blockchainweek.jp and http://offdevcon.com and we (Kickback and local venue providers) are planning to make our own calendar.
The big motive of why multiple calendars pop up (rather than they coordinate to create one single one) is that each calendar usually want to promote their own events. Having full control of the calendar have better exposure within the calendar.
I think what would be more interesting is to have event DAOs which group like minded event organisers into a single DAO and coordinate together on finding sponsorship , speakers, venues, and also trying to avoid time conflicts (which has a side effect of the DAO itself acting as TCR) . I put more thoughts about the topic on this blog https://medium.com/wearekickback/the-birth-of-devcon5-event-dao-fca71759cd9b which I concluded that we could use Moloch/MetacartelDAO itself.