Why can we not access elements of a tuple by index

Question

tuple <int, string, int> x=make_tuple(1, "anukul", 100);
cout << x[0];       //1
cout << get<0>(x);  //2

2 works. 1 does not.

Why is that?

I discovered from Lounge C++ that the compiler is probably at fault for not knowing what data type is stored at that index. 

The compiler could just look up the definition of that tuple and determine the data type or perform other operations when accessing the members of other data structures by index, so that didn't make much sense to me.