I agree that it is a long way until we know exactly how Liquid Democracy can solve the problems we have today. But the only way to get there is to implement it, get data and analyse it. This way we will be able to determine what works and what doesn’t, and we will be able to either prove/disprove our current assumptions.
But as for your criticism, you cannot compare the existing democracy model to Liquid Democracy. The low voter turnout is exactly the example I have used to explain what is wrong with democracy today and how Liquid Democracy will solve these problems.
Today many people, especially the youth, are misrepresented and they don’t feel that anyone politicians shares their views and opinions (I am one of these, I have personally never voted for this exact reason). Because of this they opt-out of the collective decision making and don’t vote at all. This is because they have to choose a representative from a limited set of politicians. If nobody shares your views, you obviously do not vote at all.
This problem is exactly solved with Liquid Democracy.
Either way. It is not about being pessimistic. It is about staying objective and doubt everything until there is nothing more to doubt. That is what I’m doing right now.