Six hundred guests versus three thousand, and the harbours that difference opens up.
The case for small-ship sailing is not really about service levels, though those follow. It is about where the ship can physically go.
Large ships anchor offshore and tender guests in, which costs an hour at each end of the day. Smaller vessels berth in the town itself, and the day starts when you step off.
Groups who want dinner ashore rather than a schedule, and anyone who has done one large-ship sailing and found the scale wearing.