Respectfully, this comment solidifies why iMessage is superior. Try sending a 4K HDR video, or low-quality video, files, or photos with a resolution greater than a Nokia phone from 10 years ago, or a multitude of other things over SMS.

Signal, WhatsApp, etc. don't come close to what iMessage offers seamlessly. For iPhone/macOS/iPadOS users, SMS is garbage. Yes, it's a closed system; but it works without a cell signal or roaming charges anywhere in the world over WiFi for free.

RCS seems like a half-baked attempt at catching up with features that've existed since 2011 on one platform. Even third-party messaging apps fail miserably compared to iMessage.