Lightning's fucked, but not dead. I don't see why it would be. There's just too much support for the network, and they're filled with capable devs that could take from where Riard will leave. Plus at the end of the day he's not the glue that puts everything together, long as there's people who are willing to improve upon Lightning Network cause just as what MK4 has said it's far from perfect, it will remain functional and pretty much alive. In the event that it does die, I don't think it connotes to anything other than previous efforts about Layer 2 solutions being moot.

Too much sensationalization and fearmongering for a topic that's not really that scary when you look at it with a magnifying glass.