During the Big Bang, after 10⁻⁵ seconds (ten millionths of a second), the quarks came together to form protons and neutrons. The antiquarks did the same, forming antiprotons.
But for every 10 billion antiprotons, the Universe contained 10 billion and 1 protons. The protons and antiprotons collided, and in the process, almost all of the antimatter was destroyed, leaving matter as dominant.
That’s the danger of allowing a competitor to achieve even a slight advantage.