Well I mean you're just wrong, you can look at any of those languages (or https://en.wikipedia.org/wiki/Benevolent_dictator_for_life). Python is over 30 years old and it's going fine. You don't see people ragging on Guido everywhere. But everyone pokes fun at the C++ committee and the wacky shit they cook up.
Design by committee just sucks. Coordinating and working with people is expensive, and a drag. If you have to, you have to, but for many projects you don't and shouldn't. An individual's design is always going to be more cohesive, and we can see it clearly looking at PL history IMO.
Guido stepped down from that role 8 years ago. It now has a 5-member steering council along with the core developers as the primary maintainers and decision makers.
That said, I'd agree with GP that design by committee does suck and I'm not impressed with several of the decisions the SC has made since.