I think they tried to amass some depth, it just unfortunately all ended up being s***. White got hurt and never regained his ability to retire even minor league hitters, Hutchison wasn't lighting the world on fire and then opted out, Zulueta couldn't find the strike zone, Thompson continued being awful even in AAA, Hatch was turned into a reliever, etc. I don't think there is an exact science to accumulating quality depth aside from developing it yourself, and the organization's top starting prospects are still in AA and below.