Why do trade associations fail so often?

Dear all, I'm new to the forum, so I'm not sure if this is the right thread to post, if not, please excuse me :)

I recently separated from my former employer and decided to start my own business. I was soon contacted by a provider that I often hired while working at my old company. I had a similar idea, just that I had some accounts that wanted to spread the business to areas in which I had no experience and which are my specialty. We talked about the opening of a company that would cover this area of ​​business, I have the technical knowledge and she the buyers. We started working on some points already, but nothing official yet. In addition, I must mention that our business relationship in recent years was always good and we even became friends. During our meetings it became clear that we seem to share the vision and enthusiasm.

However, very often this person is difficult to contact (by phone, mail … etc), seems to have many other responsibilities and / or has problems to prioritize. This has intensified in the last month and I am beginning to question his dedication to the project.

On the other hand, today I had a conversation with an old friend and former colleague who has been convincing me to start a business together for years. Today again, she insisted that we should do something together.

My biggest concern is "What's in it for me?" The person I described for the first time has business and contacts, and is the kind of person / professional who stands out in everything he does, very capable but easily distracted. The other person has no buyers or contacts, but he is very consistent and I think he has good management skills.

Is it better to go with the person who has contacts and businesses ready (knowing that I will have to invest more energy to keep it on track) or the person who is not contributing anything to the agreement but who is a strong and focused person? I must add that I trust both equally.

Or, do you advise me to start on my own?

I would be very grateful for any of your thoughts on this, thank you very much in advance! :)