Essentially a group of benevolent dictators? It would definitely be dramatically more efficient... but you lose the checks and balances that 'should' prevent, say, the singular group waging a genocide on a portion of the population.
The CCP is a pretty good example of exactly what you're describing... they've achieved incredible infrastructure that are impossible for most other countries... but they also disappear journalists, critics, enslave minority groups and bulldoze anyone that gets in the way.
Governance is just so hard to both get right and stay right. People are kind of the worst.