Most of us aren't in Silicon Valley. The cost isn't the funding or the talent density. It's the absence of thinking partners, an early audience, and a norm of generous critique.
The standard advice is to pick one project and commit. I haven't, and I've stopped pretending I'm about to. A working constraint instead of a strategy.
Most of the valuable things I have learned from building came from the projects that made it to production. The gap between shipping and not shipping is where the real lessons live.