WhatsApp is a platform; RCS is a protocol. In WhatsApp, Meta acts as the central authority. That makes it easy to build “super admin” tools like muting a thread, deleting spam for everyone, or creating announcement-only channels. The server enforces the rules.
RCS, by contrast, is a multi-operator federated system. It relies on handshakes between carriers (AT&T, Verizon, T-Mobile), hubs (Google Jibe and Apple’s own hub) and for business messaging, the CPaaS providers.
This creates real constraints. With no single central “brain,” implementing complex governance is hard. One person’s Verizon phone has to agree with another person’s T-Mobile phone on who has admin rights.
As a consequence, in the current implementation, group chats are generally capped at around 100 participants, and it doesn’t yet offer the command-and-control features large communities need. You can add or remove people, but you can’t reliably mute a loudmouth or freeze a thread.
These are operator implementation decisions, not necessarily protocol limits. The GSMA RCS group is working to support stronger group management and “community” features. But standardizing a feature across hundreds of carriers and device makers takes time.
WhatsApp ships code on Tuesday, and it works the next day. The GSMA ships a spec on Tuesday, and it often takes eighteen months to reach your phone. By the time RCS adds a Mute button, WhatsApp may have already reinvented the town square again.