为什么在c++中继承单例时没有调用子函数

#include <iostream>

class Singleton {
public:
    static Singleton& getInstance() {
        static Singleton instance;
        return instance;
    }

    virtual void doSomething() {
        std::cout << "Singleton::doSomething()" << std::endl;
    }

protected:
    Singleton() {}
    virtual ~Singleton() {}

private:
    Singleton(const Singleton&) = delete;
    Singleton& operator=(const Singleton&) = delete;
};

class DerivedSingleton : public Singleton {
public:
    void doSomething() override {
        std::cout << "DerivedSingleton::doSomething()" << std::endl;
    }
};

int main() {
    Singleton& singleton = DerivedSingleton::getInstance();
    singleton.doSomething(); // 输出: DerivedSingleton::doSomething()
    return 0;
}