Well, that explains the PLM, then.
Yeah, I'd read about the SmartHome PLMs on their site. "We have identified an issue... To prevent such an issue from occurring we introduced a hardware change...", but no offers to make owners of the defective devices whole. This, the unacceptable behaviour of the BoosterLinc I bought from them, and the pre-Insteon serial device I have that "hears" but does not "talk," that literally died sitting in a desk drawer, causes me to shy away from SmartHome products. IMO their products are not well-designed or well-built, and SH does not stand behind them. To add insult to injury: They charge top dollar for their stuff.
As for how long X10 will remain extant: Who knows? In my case it's not a question of not wanting to replace it, but not being able to justify an outlay in excess of $650 just in wall switches, appliance modules, and lamp dimmer modules, alone. Never mind the four controllers in use, one of which has an IR receiver that enables us to control lighting levels in the family room, which, oddly enough, nobody else has seen fit to replicate--other than UD... on a $300+ device.
It's like the one smart home device manufacturer, don't recall whom it was or what protocol, that had no appliance modules in their product line. Srsly?