SMS can't do group texting. It can't do images, video, or anything other than a short message (140 to 180 characters depending on your language).
MMS followed SMS and it can do group texting. However, attachment sizes are laughably small, leading to 160p videos being compressed to hell to make it across the tiny video size limits.
MMS also used to cost more in some places. My carrier simply shut it down a couple of years ago because nobody was using it (I live in a WhatsApp country).
RCS is the official next generation of SMS/MMS, made by the people who define standards like 3G/4G/5G. Basically MMS 2.0. Very few carrière launched RCS services when they rolled out 4G, even fewer phones had RCS clients, so you ended up with needing to download your carrier's (inferior) messaging app to maybe exchange RCS messages with other people if they also downloaded their carrier's apps.
SMS still works and has always worked.