The market depth tool for Exchange Traded Funds displays a maximum of 5 orders at any one time. This is intentional and does not mean there is a lack of trading activity.
The tool is designed to show a snapshot of the most active orders in the market rather than a full list. Exchange Traded Funds are liquid investments supported by market makers who continuously manage supply and demand, so the limited display reflects the design of the tool, not the availability of the ETF.