Beyond the current technical limitations, which will one day no longer be an issue, I would imagine there are a lot of logistical issues with this. First off, a site allowing realistic deep fake / face swap would probably be open to a huge amount of liability in being sued by whomever you decided to put their face on. Also, as mentioned above, the ability for you to easily create whatever you wanted to your own desire would potentially put the industry out of business. Actual demand for real models would plummet and they wouldn't get nearly as much work anymore. The companies themselves would probably be ok, as they could just charge a large amount per scene generated, but the actual workers would suffer.
