> And they're effectively saying they've had enough of running call centers, tracing lost parcels, weirdo customers who show up at the factory, running marketing campaigns etc.

When this is a company's core complaint, then the usual strategy for getting out of the D2C business (without losing D2C revenue) is finding a channel partner willing to absorb the dealflow. I.e. turning your B2C channel into a single B2B(2C) enterprise customer.