Much as I'd like to side with labor here, the companies are probably right. Even if the linchpin is high level and happy, building around a single, irreplaceable employee is not a sound long term strategy.

For all the important contributions Steve Jobs made to Apple when he returned, maybe the least heralded and hardest to implement is that he managed to NOT make himself irreplaceable. To many people's surprise, Apple did not collapse after his retirement and death. So maybe his most genius contribution was not to make Apple dependent on his ongoing genius contributions.