Maybe there'll be a yet to be discovered way for channels to never have to go on chain again, but there'll always be on chain needs.
That's what the whole Lightning Network concept has always been based on: users can hop channels.
So, if I've got a channel with you gentlemand, and you've got a channel with ChromticStar, I can send BTC to ChromaticStar via the channel I have with you. And so everyone can send to anyone, as long as there's a viable route across the network.