My China bomb story, could I have prevented it.

Lower pressure is not the way to go. With higher temperatures outdoors and lower pressures, the tires will overheat even more due to additional flex. Heat is the main killer of tires. Your tires were just over 6 years old and chances are they spent too much time just sitting and drying out. Any trailer tires over 5 years old are past their prime and should be replaced regardless of how good they look... particularly if they have not been used year round on a regular basis.