As a 10x engineer, hard disagree. The modern stack is just too large. Sure, building out an MVP can be done by one 10x engineer, because basically any prototype can be built by a single engineer. But making the UX aesthetically beautiful, adding a test suite (at least for automatic dependency updating), adding observability and alerting, performance optimization, persistence optimization, cost/deployment optimization, day-to-day maintenance automations, architecture and network diagrams, tutorial/how-to/explanation/reference documentation.... you are delusional if you think that can all be delivered, at consistently high quality, by a single engineer.

You can have a single genuinely senior 10x engineer oversee all those efforts, executed by "normal" engineers. But no, not execute them all by the 10x engineer's self.