To use a mathematical simile: the Torah can be likened to a high-level equation that gives room to numerous different answers, all of which are correct.
Every halachic decision, then, is not the one and only possible and absolutely true solution; rather it is one that can suit the existential physicality of our world, one practically applicable solution to a specific problem.
This explains what the Talmud tells us — that in our world, halacha is decided according to the House of Hillel, but in the future, it will be decided according to the House of Shammai.
The House of Hillel’s method of reaching legal rulings is geared toward our reality.
But in the times to come, when the world as a whole will have changed drastically, it will also need different halachic solutions.
And even though now we do not practice these different solutions, they exist as possible and true solutions that will be applicable in a different reality.
–Rabbi Adin Steinsaltz