I think at $29 a month we should be able to add one collaborator to the personal plan, at the end of the day, two people work quicker than one and once the website gets completed and published and presumably picks up traffic and generates some revenue, more sites will eventually move to the professional plan.
I feel for you @Liam because I see where you are coming from. In many ways, it makes sense to have collaborators in everything we do. I also started out on the personal plan and quickly upgraded my plan to take advantage of collaborators. On the Bubble side, they are looking for ways to differentiate an individual developer from a team/professional. Collaboration is one of those key differences.
As far as functionality, Bubble is currently balancing growth and profits with functionality. They give a lot for $29 a month and I don’t see them adding collaboration to the personal plan in the near future.
I will say that I believe Agencies can collaborate with your app even on the personal plan.