It isn't because no-one proposed it.
If proposed, it would introduce an ambiguity with the ternary ( ? : ) operator.
E.g., what does
f?
g?h:i;
mean?
Is it the same as
f ? g?h : i; // ternary operator where `g?h` is a single ident
or with semicolon insertion the same as
f?;
g?h : i; // a labelled statement
Picking either interpretation would require a lot of parse-ahead or context-sensitivity in the lexer.