Everyone knows that X in these two sentences originally referred to "The King". However, the sentences should be interpreted as "The (old) King is dead. Long live the (new) King."<p>Substituting (JavaScript|Java|C#|SilverLight|Flash|etc.) for X doesn't really make sense.
Sure it does. C# 2 comes out X(old King) refers to C# 1 and X(new King) refers to C# 2. It pretty much is true in the case of C# as soon as a new version is released the old version is dead, there is zero talk about the last version with everything either focused on the current release or the next release.
To my knowledge, the original phrase was intended to make the new king throned immediately after the discovery of the death of the previous king. Unfortunately there's no real atomicity in spoken language ...<p>As far as the idiom is concerned, it makes perfect sense if you think about the second usage as the set of problems for which the language is commonly used to solve. Take for example JavaScript:<p>Javascript (the original language) is dead. Long live Javascript (the successor language for the problem of client-side scripting).<p>This would be a great title for an article about a scripting language like coffeescript