Has spear & shield any advantages compared to pikes?

Why not just duel wield two shields instead?

cant stop arrows with your pike

samurai jack could

Why not use a Cataphract instead?

Easier to train peasants. Pikes require some level of professionalism.

it fell out of favor when body armor reached the point of being nigh impervious to most weapons. at that point two handed weapons became the norm.

Depends on your numbers. A single line of pikemen vs. a single line of spearmen/hoplites would lose to the spearmen. The depth and mass of pikes could present real issues to frontal attacks. That also locks the pike formation into a single formation. If they want to suddenly shift, it would involve coordinating several to hundreds of men in a matter of moments. Otherwise the pikes would all bump into one another or the men themselves. A mass of spearmen have a little more flexibility to defend and attack.

Larger pikes require both hands to operate. That is great for the force of a thrust... but limits the use of a defensive shield. If I was about to hurl a stone or javelin at your face you would have to elevate your entire pike to raise the shield... or let go in order get that shield up. A hoplite or simple spearman could just lift the shield while maintaining their weapon in the other hand. Again, this is just general

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If you do have professionals using the pikes, you can drill the to repel a great deal of enemy attacks. Even chariots: an infantry's worst nightmare in a massed charge

The pike is utterly useless out of formation. This means that in the pikes are incapable of really defending themselves in Push of Pike. They'll have to drop their pikes to use other weapons. On uneven ground, when flanked, or just when plain broken pikemen have virtually no avenue of defense against an infantry or cavalry formation from a direction other than the place presented with pikes. In later pike formation this was less of an issue as everyone maneuvered in giant squares but in antiquity this was literally what killed the phalangites.

But simple spear and shield infantry massed together is as old as organized warfare itself. It is effective

With the spear and shield, you can protec, but also attac.

After all, there can be a lot of mastery behind a warrior wielding a spear. Or it could be a dude who was handed a pointy stick and told to point it at *them*

Alexander.
>he protec
>he attac
>but most importantly, he leaves no heir for his empire so it dissolves into civil war

This user speaks truth

I really hesitate to blame racism for the diadochi's inflexibility like your pic does. It may have played a role, but the diadochi didn't actually neglect the importance of levies on their forces. The Seleucids, for example, fielded Arabians, Persians, Agrianians, Carmanians, Daae, Cilicians and Greeks, Ptolemites used Cretans, Libyans, Native Egyptians and Thracian, and the Bactrians had a massive cavalry wing (I've seen the estimation that as much as a two thirds of the Bactrian army was composed of cavalry in some battles, but can't remember the citation for it) made up of native tribesmen. In all three of these cases, the phalanx was always formed by Macedonians who had settled in those lands and formed colonies, not by the levies. For the life of me I can only think of one example of a phalanx being made of native levies, which was the native phalanx the Egyptians used at the Battle of Raphia to support their larger Macedonian phalanx.

The true reason for the later phalanx's inflexibility comes down to two major reasons (in my opinion that is, it's worth mentioning that it's entirely possible for reasonable people to disagree on this). Firstly, almost all the successor states neglected the hetairoi, using them solely as a cavalry bodyguard as mentioned in that image. That's not entirely the fault of timidity however, often the diadochi didn't have the ability to field any significant number of hetairoi due to lacking the social infrastructure. Hetairoi are extremely comparable to later western knights due to being recruited from feudal land-owners. In many of the successor states they simply didn't have the same same social structure as Macedon, making it extremely hard to recruit and train skilled heavy cavalry. Secondly, phalanxes themselves underwent serious evolution. Because so much warfare between the diadochi was phalanx on phalanx, they began evolving to more effectively counter other phalanxes. TBC

These developments took the form of ever longer sarissas in order to hold the opposing phalanx at bay, and heavier armour to make their own phalanx harder to rout. Consequently, the later diadochi phalanxes were far sturdier than Alexander's ones had been, but also far less maneuverable. Where Alexander had managed to fight across a river at the Battle of the Hydaspes, the diadochi phalanxes shattered when trying to chase the Romans into uneven ground at Pydna. Combine these factors and you're left with no hammer and an inflexible anvil.

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Why not dual-wield greatswords?

Dual wield glaives, bruh

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But surely, with all that diversity, they would have had some sort of offensive infantry to replace the hypaspists, and some sort of skilled light or medium cavalry, not to mention horse archers.