This kind of first order reasoning is nice, but the reality of software economics is a tad bit more complex. The assumption that the market is large, that the commons helps everybody sort of equally are not true in a lot of sectors. Namely, as IT transforms itself a lot of things become almost zero-marginal-cost. Starting a new server? Setting up a new database? Backup/Snapshot? Load balancing? Scaling? Just click that AWS web console shit, and you're good to go. And this out-competes the others.
I'm not saying that changing licenses is super-A-OK, but the fact is the license was never good in the first place, because it failed to take into account what will happen when AWS starts to offer MongoDB.
Furthermore, I have no problem with anyone holding the view that MongoDB should then compete with AWS, and/or focus on on-premise computing, and/or slowly pivot away from building MongoDB itself to whatever. But anyone holding this view should recognize the aforementioned reality that cloud computing is happening, IT is not just a hydra, it's an ouroboros too, it's eating itself.