Why does modern bluetooth audio need lossy compression?
One of the primary targets of the Bluetooth specifications is low power (small battery) and physically tiny devices.  Bandwidth beyond that perceivable by the user (via very small audio transducers) wastes RF transmitter and receiver battery power.  Compression reduces the required bandwidth.  What is considered perceivable is usually measured by A/B user testing, not by theoretical quantization noise metrics.

So, at least in part, it's likely a marketable audio quality versus battery life trade-off.