Assuming that they are the market. Unless you’re designing a product for affluent people who work in tech in the Bay Area and use 27″ screens with the latest hardware, chances are that your product will not work in the mass market. For most people, technology is a means, not an end. They don’t care about how things are done, just that they are done. Google’s failures with Buzz, Wave and Google+ are great examples of this. They tested well among Google’s employees, but failed in the marketplace.
Assuming that San Francisco is the market. Again, you’re targeting an affluent market that is willing to try just about anything. There’s also density that enables a lot of business models that won’t work in the suburbs or exurbs. If it works in San Francisco, that just means it works in San Francisco. Will your product work in a red state? That’s one of the keys to making a great business. Get out of the city and try doing market research in Minneapolis or Austin. Nextdoor is a great example of success — when I talk to my friends in St. Paul, they love the product.
Assuming that users will make big changes quickly. The mainstream customer can take months or years to adopt a new product. Take Twitter. It was founded in 2006 and it’s still struggling to find Product Market Fit among normals. Fortunately for Twitter, the media has had an ongoing love affair with the product and it gets billions in free media. Unfortunately for Twitter investors, all of that free media exposure doesn’t translate into the number of users and revenue that Facebook generates. I used to call Twitter “the command line interface for communications.” It’s gotten much better, but it’s still complex. Complex products will take longer to gain adoption than easy-to-grok products like Snapchat and Instagram.
Assuming that rules and regulations won’t change. Uber and Airbnb are the best examples of this. Build a product that people love and eventually laws will get changed. They’ll change faster if you get involved in the legislative process instead of just viewing politicians as out-of-touch people who “don’t get it.” It’s your job to educate the them. Uber and Airbnb have been masterful in government relations and political campaigning.
Failing to taking into account Moore’s Law. Technology gets cheaper, better and faster. This happens at a rapid pace. Especially when it comes to designing hardware products, this is key. The goal is to optimize over the product lifecycle, not necessarily the initial product costs. Products like XBox assume an initial loss on hardware that gets made up with software and declining BOM.