Most democracies have elections every 4 or 5 years. That is good, in that we can get rid of underperforming politicians and parties. But it is bad, in that there isn't a lot of incentive for politicians and parties to plan over a longer timescale than 4 or 5 years.
China has the opposite problem. It can plan and finance long term projects. But there is little prospect of peacefully changing the leadership.
Long-term planning on a colossal scale (like nation-state-level) (or even on a not-so-colossal scale - think of how many plans YOU have made and how they turned out) is pointless because of black swans
Sure, having a general idea of where you want things to go is fine, and everyone already does that; but when a government starts thinking that they should set a concrete goal X and they should do Y to achieve it, it's just akin to trying to predict the future, and we all know how well that always works out, because theyre under the faulty premise of thinkin Y will be constant forever, or that even the goal itself (X) should remain constant in a world that is anything but constant
So, this is a terrible argument for not having elections, or bigger election cycles. I'm sure someone could potentially put forward a better argument, but this one is not it