Conduit is also licensed under Apache 2.0, so it could also be taken closed source at any point in time. The reason this wouldn’t impact Conduit as much is that there’re other contributors, whilst Synapse and Dendrite are almost exclusively developed by Element.

Right. The current perspective is based on the idea that if Synapse/Dendrite go closed-source right now, an open source version would be good as dead. Element is responsible for 95% of Synapse/Dendrite and I'm sure a community fork would have to play a lot of catch-up to figure out how to keep it going. If the community was more involved in Synapse/Dendrite implementation (and if Element let them) there would be less cause for alarm, as closing the source would just mean an immediate community fork and putting Element on ignore. Also to reiterate, The Matrix Foundation is not going along with Element on this move, and even if Element pulled something shady the Matrix Core Spec etc. would still remain open and under the Foundation's control, so the max we have to lose is Synapse/Dendrite and all of Element's developers.

As for the rest I agree and I do actually trust that Element is simply playing their only card here. These maneuvers are all required in order for Element to survive as a company at all, but they also unfortunately leave this backdoor open as a consequence. Matthew has pinky-promised over and over that they are only acting in good faith and that they would never use the backdoor, but it's understandable that the presence of the backdoor is putting everyone at unease. Best case scenario we take this as a warning sign that if Element drops dead tomorrow then Matrix is also dead. If people want Matrix to not be practically owned by Element then we should diversify and prepare escape plans.