Are you serious?
Yes Egyptian caps are OP for income, but theyre useless hammers & so everyone who does Egyptian with hammer has massive risk of being chiefed in their non-cap and losing their hammer --- OR you get ghosted since tyou dont have auto-dodge --- This is a massive counter to it (especially on a 10x server)
Slaves are cheapest yes, but theyre useless unless you're constantly losing defence, if those slaves survive more than a week on 1x speed then youre better off building ash wardens for because they amount they eat compared to how much they defend is rediculously bad.
RC - While they have a strong balanced defence, they are the slowest defensive unit to train, cost 3 crop (with nothing to reduce it like roman), and cost the most to produce, and their travel speed is pretty average compared to others.
Ash warden - They have +5 more defence in total than Phals but take more than an extra 2min to produce, Spears have the same total defence than them and 2mins quicker to produce almost...
My point is that Egyptian units cost more usually, and take longer to produce, with minimal added defence
and if you want speed, you've got the slave, which - if you're in a sluggy war with an alliance can be useful if you keep losing your defence and need some QUICK, but theyre cheap and worthless
its like comparing clubs and axemen.