Not more expensive, more difficult to source. IME - mid level sys admin/eng job code will get 10-20% less compensation than an SDE. A principle level SEs comp will also top out before an SDE.
For junior or mid level SE I've seen about 10% of candidates meet the hiring bar. SDEs I've had less involvement, but I'd hazard 20% get an offer where I've been.
The other problem is the pipeline. Colleges keep
Pumping out SDE candidates from comp sci and maths. These junior SDEs will also have a reasonably consistent skill set and experience. There are (effectively) no colleges or curriculum creating new SEs. The incoming candidates also vary widely in their depth and breadth of relevant knowledge. Pretty sure that contributes to the higher negative signal.
For junior or mid level SE I've seen about 10% of candidates meet the hiring bar. SDEs I've had less involvement, but I'd hazard 20% get an offer where I've been.
The other problem is the pipeline. Colleges keep Pumping out SDE candidates from comp sci and maths. These junior SDEs will also have a reasonably consistent skill set and experience. There are (effectively) no colleges or curriculum creating new SEs. The incoming candidates also vary widely in their depth and breadth of relevant knowledge. Pretty sure that contributes to the higher negative signal.