The change may be due to Verizon dropping support for RCS as Samsung Messages depends on the carrier for RCS, while Google Messages relies on Google's own RCS servers.

Samsung confirmed earlier this year that Google Messages would be the new default texting app for its phones. This change meant that more users would be directed towards Google Messages, and one naturally expected Samsung to deprioritize the development of the Samsung Messages app. However, you could still use Samsung Messages for RCS if you really wanted to. For users who prefer Samsung Messages over Google Messages, there's bad news coming your way, as Samsung Messages seems to be dropping support for RCS in 2025.