And ravioli you can heat in the microwave is more convenient than eating at an Italian restaurant. Your move, sir.
My homemade Italian ravioli are true deliciousness, the canned ones are a bad imitation..
The maesters own a factory, they mass produce - with a scaling and efficient process - a product that is good enough for the purpose it's sold.
Trying to sell niche products as u suggests it's not profitable right now :
- anything more specialised would require way more expensive equipment, especially knights
- absence of strong concurrents in the free market simply removes the need for specialisation of their own product.. it ain't like they would sell more units, the customers are still limited to Essos
- the failing rate of producing niche soldiers would the higher because their experience in that field is lower, hence less profits and higher production costs
- in general the entire production process would be more expensive
- the benefit of selling them at higher prices is arguable : newer models would represent a newer brand of products that would not yet be proved into battlefield, the customers might not be willingly to adopt new types of soldiers in great numbers. Many customers might still prefer quantity over "specialisation", ten unsullied are still better than a single Knight unsullied.
You claim that their way of mass producing unsullied is stupid, I disagree. We have not the instruments to state whether an unsullied can be shaped as he is in mind and body if the maester don't put them through the experiences they are out through: killing puppies, infants, having their pénis cut down. The latter me get be a fundamental requirement, removing genitals might be compulsory to obtaining a man who never disobeys and feels no desire, rather than accessory. They surely believe this is fundamental, or they wouldn't practice it since it's expensive.
Discarding the 'defective' products might again be the only way to ensure they have a quality product that does what is asked for. It's true that they are wealthy and there is abundance of slaves, but contrary to common beliefs all merchants and entrepreneurs are able to do math very well. They wouldn't give up the prospect of profits if that wasn't a necessary way to go.
So no, they are not morons and they have no reason to change their best product into something else right now.