They need to mitigate business risk so they look for vendors that will: 1. Exist as long as their solution is being used 2. Provide adequate support 3. Are legally accountable for their products and services 4. Have the proper processes in place for things like billing and invoices
Having raw talent is just part of the business puzzle. There are a lot of start-ups or freelancers that can "fake it until they make it" but it's because they really understand how a small business or corporation makes buying decisions.