Legion vs. Phalanx

[Parallel Pain]

No the pikes in the 17th century were often 4 facing instead of 1, and frequently had men armed with swords and bucklers and other such weapons operating in the same unit amongst the pikemen.
The phalanx did not outlive the cohort. The pike outlived the cohort.

And the sword outlived the pike

Besides of which 17th century pike was basically used to protect arquebus from cavalry. Once the bayonet came along it faded back into oblivion

As for arguing chariot vs cavalry and bow vs gun, there isn't even an argument. Chariot is too inflexible. It need a very long path to accelerate, must operate on terrain free of ANY obstruction (even more so than cavalry) is slower and less maneuverable than cavalry. So once horses became large enough for charging purpose chariots faded out.
Guns have more armor penetration power than the bow, can be mass equiped and trained a lot more efficiently than the bow, can be used from cover, and helps in centralization.