When I show people that I can talk to Signal, WhatsApp, and Signal through a single app, they're pretty impressed. I wouldn't expect most people to set up a Matrix bridging system like I did, same with most Mastodon servers, but it's a feature people do generally want.
With Mastodon, most people first ask "but how do I follow people on Twitter", which often leads to pointing at bridges that may stop working at any point and have no official status, and often get blocked on small servers because of the overwhelming wave of moderation spam they cause.
Phone manufacturers back in the day used to have quite commonly used "social hub" apps that would combine various social media sources into a single UI, but they were all tied to their own brand that either got too difficult to maintain or lost the phone wars (HTC and Blackberry had quite well-received integrations if I recall).
The past years we've been stuck with a locked in ecosystem for so long that the mere idea of two different apps interoperating has become inconceivable to the mainstream.
I hope the DMA, which will force messenger apps to interoperate, will bring back the knowledge that it's possible to do so at the very least.