Z-wave was introduced in 1998 as an alternative to ZigBee, which had not yet been ratified (a process that took six years) Z-wave, unlike ZigBee, Bluetooth and WiFi, is a proprietary standard, meaning Z-wave silicon must be procured from a single supplier. That supplier elected to manufacture their own modules. Panasonic had produced a Z-wave module for nearly 15 years, exited this market, since it was impossible to compete against a silicon supplier, from which Panasonic purchased the Z-Wave controller IC, that was also making modules.
Panasonic no longer offers a Z-wave module. Z-Wave technology was superseded by ZigBee over a decade ago, and Bluetooth MESH will most likely displace ZigBee.
Proprietary standards (Z-Wave, ANT) are designed to eliminate competition from both silicon and module manufacturers and IMHO are standards that should be avoided when ever possible.