Earlier quoted context omitted.
Because this would be incredibly expensive and the lawyer would end up doing nothing like 70% of the time.
Hiring an experienced lawyer away from a job as general counsel or from an established law firm would be incredibly expensive. Hiring a more junior one (or bringing a moderately experienced lawyer onto the board), not so much. As for the workload, that's a bit like saying there's no point in having a CIO because all the computers work fine 95% of the time.
Every single time I see someone try to use an analogy lately I just stare in bewilderment.