我对模板类的显式实例化似乎不起作用

#include <iostream>

template <class T>
struct less_than_comparable {
    friend bool operator>=(T const& a, T const& b) {
        return !(a < b);
    }
};

class Point {
    friend bool operator<(Point const& a, Point const& b) {
        return a.x_ < b.x_;
    }

public:
    Point(int x) : x_(x) {}

private:
    int x_;
};

template struct less_than_comparable<Point>; 
//Here I explicitly instantiate a template class expecting that 
//less_han_comparable<Point> would export opeartor>=() for class Point to the global
//namespace, and then the p1 >= p2 statement will work as expected.

int main() {
    using namespace std;

    Point p1(1), p2(2);
    cout << (p1 < p2) << endl;
    cout << (p1 >= p2) << endl; //But I have a compiler error here saying that 
                                //no match for ‘operator>=’ in ‘p1 >= p2’
}