> they say it's at cost but it feels like a premium/markup on London prices, not a city known for being cheap!
If you've ever looked at housing (or anything else) in the SFBA, yes, it's more expensive than even London. (Salaries are higher too).
> Surely most people dropping work to focus on blogging would be looking for minimal costs (whilst they have limited income as they hone a skill) rather than maximal costs?!
Maybe. In my experience when you're trying to switch careers, getting to the point where you can earn income (or discover that you can't) as quickly as possible is more effective than trying to extend your runway by cutting expenses. Others may make a different judgement call.