Great post.
It's important to be close to your customers. If your customers are in SF, then being in SF can make sense. Another reason why you may want to be in SF is you need access to SaaS veterans at the VP level.
Having someone in the team who has already done it is the best growth hack.
But then, NY is getting as good as SF for that, and, you get to live in an awesome city (I live in NY).
All other reasons often raised like "pool of developers" or proximity to investors are BS.
Like mentioned in the post, you don't need to be close to developers and having coffees with investors is a waste of time especially in the early stages.
I lived for 3 months in SF. It was very unpleasant. The reasons are listed in the comments and in the post. And I am affluent enough to afford to live alone in a 1BR, dine out, drive my way around.
Raised money, got the hell out back to the east coast.