A democracy doesn't prevent long-term planning if only the electorate appreciates long-term projects. Democracies can build stuff across parliaments if differences between parties aren't so overwhelming so as to the majority of them can agree on developing something even if the relative power of elected parties varies over terms.

In a lot of countries the major parties agree on many core views and social code because they share a common nation/society, and the political differences happen merely on the edges or linings of the value spectrum. A government of highly polarised parties voted by a highly heterogeneous pool of voters is not ideal for long-term efforts.