What's a post X10 world? Even if X10 stopped making x10, I'd bet there would still be other companies out there making the products.
Seems to me that X10 (the company) had one little hiccup, and the whole world wants to jump ship on the mother of all HA protocols. In turn, places like SmartLabs can all sell us on much more expensive products.
Read what Dave W said in his above post. No HA is without faults. Fortunately, us x10 users have Jeff Volp who designs and sells all kind of gizmos that make x10 as reliable as it was before cheap switching power supplies and other x10 problem causers. Just read about Volp's products carefully, as each work with a different problem. For most of us, the XTB-IIR repeater/coupler is enough to solve the problems and then some.
Even on a budget, filters can still be found relatively cheap. If you can track down the culprit, filters work wonders.
I just can't believe that someone would call x10 dead. For a young geezer like myself, x10 will always be there for me.