In a real system, losses due to retransmission and signaling packets interfering with data flow will also reduce the data rate. Devices such as LAN access points might spend time doing inquiry scanning and page scanning to allow more devices to connect. This will use up time lowering the bandwidth available for data transfer.
Applications that just want to connect, transfer data, and disconnect will spend substantial time inquiring, paging, performing service discovery, and configuring links before they can even begin using link bandwidth for data transfer.
The symbol rate when a Bluetooth device is transmitting is 1 megabit per second, but, as we've seen, the real data rate at an application will be much less than this. The data rate is affected by many factors. These factors will vary from one application to another and according to distance, propagation, and interference conditions, which explains why you will see many different figures quoted for Bluetooth data rates.