Thanks Avi, good summary. To back up a level, the choice of a license could be made, I suppose, at the committee level or at the individual contributor or product level. It's called the "Open Source Committee", so it's probably not controversial for us to plug some kind of open source license at the committee level.
On the other hand, it may not be necessary for the committee to encourage particular FLOSS licenses in advance. Often there are strong tactical reasons for some open source work to be in a particular license. For instance, both R and the ChainLadder package are GPL'd, so any code submitted to these should be GPL'd also; the stan MCMC libraries are BSD3'd so contributions to those should be BSD3'd. Conversely, if you use ChainLadder package code in your project, then the GPL copyleft would probably attach to your code, basically requiring that you use GPL also. The free software foundation has a somewhat nuanced view about which license to choose, even though they are strong GPL/AGPL advocates.
Somewhat unrelated to this point, but perhaps worth mentioning, is that a project can be dual or even triple licensed, and this sometimes makes sense. So a new project could be BSD'd and GPLv2 at the same time, partially ameliorating that incompatibility.