If it was that simple, people wouldn't have any issue with the conditional operator. The problem is there actually is a semantic difference between the two lines you wrote in most languages.

If-Then-Else is a statement. It doesn't return a value. It's just a branching operation between the two blocks.

The conditional operator is an expression. It returns a value hence it has a type. And that's where things start to be messy. Typing rules for the conditional operator are, well, not trivial and varie from language to language. Let's use an exemple from Java Puzzlers (Joshua Bloch and Neal Gafter) :

char x = 'X'; int i = 0; System.out.print(true ? x : 0); System.out.print(false ? i : x);

will print X88 but the same thing in C++

        char x = 'X';
        int i = 0;
        cout << (true ? x : 0);
        cout << (false ? i : x);

will print 8888.

And I am not even talking about the priority mess when you try to use a conditional operator in a conditional operator.