I hope you're right. I definitely think you're right in the sense that AI is going to be required to develop molecular scale machinery. The only way your timeline works though is if companies that develop and control the AI begin training on them as soon as possible. Unfortunately, I don't know for certain whether or not these AI companies share this goal.

One company that does give me some hope in that regard is DeepMind. While I don't think Demis Hassabis would come right out and say it, I think this is probably his goal and that of Page and Brin. The AlphaFold project seems to be a good start toward that goal. If you're able to make predictions about how amino acid chains will self-fold and/or assemble into proteins, you're at least part-way toward making molecular scale machine parts.

IF DeepMind begins work on this right away, we may get the molecular scale assemblers of my dreams in my lifetime. Fingers crossed.