Unlike browsers, which can (for now) still be swapped out solely on individual preference, the network effects are real for messaging platforms. This means that

Unlike browsers, which can (for now) still be swapped out solely on individual preference, the network effects are real for messaging platforms. This means that currently Signal is more broadly useful than Matrix clients. Hopefully this can change some day, and Matrix (or something like it) will become ubiquitous. But it was a slog for Signal to gain even its small market share, despite its better usability and lower barriers to entry. For lack of a better alternative, we "standardized" on Signal as the de-facto secure messaging system that is outside of the control of ad companies, and it will take time to rectify that.