We started understanding of why it works so well like 30 years after its first implementation (in the 1950's)? The paper you mention is written in the 2000s whi

We started understanding of why it works so well like 30 years after its first implementation (in the 1950's)? The paper you mention is written in the 2000s while the Simplex dominated the field from at least the 70's. Meanwhile the GP would have discarded the simplex algorithm due to its worst case performance.