The benevolent dictatorship model works great when people can vote with their feet (or their keyboards, as the case may be) whether they support the dictator in the first place. The contributors to Linux and Python have more influence over the projects than the dictators do - they continually decide whether to endorse the dictator's vision. A dictatorship of a company is much more like an actual dictatorship of a country, where you control people's lives and decide who gets to join and leave. It's more efficient, yes - but it is both less just and less incentivized to point that ruthless efficiency in the right direction.
By all means, run technical projects at work like Linux and Python are run - but give people the freedom to vote no confidence in these projects without endangering their housing and their health insurance.