MC34063 P-MOSFET driver?
When the transistors in the power path are in the darlington configuration, both of the currents flowing through the driver and the switch transistors are in the power path and the currents are not wasted in that sense. Also, the voltage drops are automatically limited by Vce of the switch transistor.

Look at the configuration in the schematic shown with DVR connected to the positive supply. When the driver transistor goes on, the current comes from the positive supply, through it, then through the B-E of the switch transistor to ground. The current is only limited by unspecified resistances of the IC. The 34063 is likely to have a short life outside of simulation.

It should not be a surprise that the 34063 is not necessarily an efficient driver for MOSFET because it is single-ended. It was introduced back when power MOSFETs were at their beginning.