I think decentralized sidechains that solve the scalability problems CAN & will exist... It looks like we may get a trustless two way peg thanks to bitVM. Which means that we can have a nearly endless number of auditable sidechains (with different privacy benefits & tradeoffs) networked via Lightning bridges.
Discussion
Ok, I honestly don't think so, but I'll leave that possibility open. But it's definitely not a Liquid, right?
The liquid federation for which anyone can run a node to verify the network, & privately peg in their own bitcoin, & also move in & out of via Lightning transactions, is a perfectly reasonable approach to adding some scale to bitcoin. But I think new developments suggest there will be even better options in the not too distant future.