Everyone is always organizing to rally against something, and that's where the problem with these platforms shows itself, it enforces conformity. Conformists are easy to control and manipulate.
This isn't just a problem with those social media platforms. Even the forum enforces conformity. For example, everyone just keeps praising and keeps saying good things about the Lightning Network despite the fact that LN is still not finding any users and is becoming over-engineered all the time.
There is desperate lack of genuine criticism even here at the forum because most of the older members wearing the sigs aren't discussing technical details but just commenting on the validity of LN at all times. These people have no idea that how actually bitcoin will scale. The ideas that get thrown around now simply do not have the same weight as they are more philosophical than technical.
That is where the answer to JetsCash's question is. If you want to bring the mojo back, you have to make it worthwhile for the devs to contribute. Most of the earliest devs are on payroll with Blockstream or other organizations. Nothing wrong in that. The lesson is that people who actually benefited from the forum should contribute to projects that aim to further bitcoin adoption.
Form a hierarchy of committed and technically sound people to guide projects. The funding should come from people who have benefited from being early adopters. Most of that crowd has moved out of the forum and are busy with their businesses etc. like Cobra pointed out. Find the champions.