Your question is in analogy with the purpose of each frame .A 30 years old racing bike cannot be compared with a tourer of the same age in terms of frame material .I believe that the majority of steel frames were decent for road bicycles,columbus reynolds etc were all good quality frames.In my hands the only frame that cracked was an aluminum gt mtb .I guess that mass production of asian factories degraded the average quality of bicycles over time.An old cheap frame is more reliable than a present fancy cheap frame,thats my oppinion on this matter.