Every user has different abilities and preferences. A human designer can only consider a small subset of them. This is the reason why all interfaces we have go from terrible to mediocre.

User interface design and implementation has to be automated. The current paradigm doesn't scale, neither for providers nor users. It's perhaps software's main bottleneck.

This is not a new idea. I'm sure many people are working on this, but I still think this is something we don't talk about enough.