Dividing the Family Spoils (Part-2)

Lord Castell would only choose to ransom the elite riders and nobles because socially they were the only ones that mattered.

There was really no need to explain why he had to rescue the latter- they were nobles, end of argument. 

While the former also had considerable wealth and thus power in Sybarian society. 

Without that, they would not have been able to even become those elite riders because the cost of everything during their training - their food, lodging, the horses and the feed and care for these horses, the wages of the instructors, etc. had to be borne by each trainee themselves.

This was a massive expense that a peasant would have a hard time affording even if he worked his whole life without spending a dime.

Not to mention, at the end of the day, it was possible they would not be even chosen for the unit. 

The most common reason was injury, like breaking an arm or leg.