All the open phones in the world won't help if you use closed-source WhatsApp / Facebook. And you kinda have to if you want to talk to your less tech savvy friends and family.
And open chat protiocols won't help because we don't have open source smartphones :) Maybe this battle is on different fronts and there are many factors that are into play.
In the EU there is a law in preparation that will force big players in chat networks to open up to third parties: The Digital Markets Act (DMA): https://ec.europa.eu/info/strategy/priorities-2019-2024/euro...