Reference

The Australian cricket team during the 1928–29 series was considered inexperienced for several reasons:

1. Youthful Players: The team included a number of younger players who lacked international experience, having not played extensively in Test matches prior to the series.

2. New Faces: Several new players were introduced to the squad, which meant that many of them were playing together for the first time at that level.

3. Changes in Leadership: There were changes or instability in leadership and team composition around that time, making it challenging for the players to build a cohesive unit.

Unfortunately, I did not find specific sources detailing these factors. However, generally, teams labeled as inexperienced often face issues related to the integration of new players and lack of exposure to high-pressure international matches, which likely contributed to this perception for the Australian team.

Here is an image related to the Australian team:

If you would like more detailed historical information, examining records from that era or visiting cricket history resources might provide more insights.