Startups are hard - setting up shop in a startup hub helps you succeed at being a startup. There's support and best practices in the air for you at being a startup, which is super super helpful. SF being the largest and most robust of these hubs provides probably the greatest support on this front.
Nevertheless, it is sometimes forgotten that startups often don't exist in a startup vacuum - they interact on a variety of levels with the world and different locations will help them succeed in these other aspects. If your startup deals with publishers, being in the location where all those publishers are helps you immensely. If you deal with fashion being in a fashion hub helps you. If you're schtick is some fancy machine learning thing, maybe you want to set up shop by MIT. Etc.
So while generically being in a startup hub will help most startups more than other locations. Specifically your startup might see greater benefit elsewhere, or not in SF or whatever. And maybe, just maybe, you don't need these environmental boosts so just go wherever the hell you want to live. It's startups, break the rules when you want to - just know what you're giving up and what you're getting in return.