The original reasoning behind a Guild was to restrict non guild members from selling their services within a guild area to protect guild members businesses. Yes, it was also established for apprentiships, training and a standard. But, in reality, Guilds became more like cartels or even franchise area's for said trades people.

As the area of trade in the WordPress ecosystem is Global. A Guild would not be appropriate. I'm certain that this is not the way to go. Here's why:

1 The guild will own products in order to make a profit to RUN the guild. This makes the guild an immediate competitor to each and every member.

2 The members will contribute to the guild via a percentage contribution. It's not crystal clear where this contribution will go.

3 The guild will work with product owners to promote, grow and monetize their products.

Effectively, in my view.
The Guild will act as a representative of product owners. Therefore, an agency representative or more accurately, a partnership manager.

Do we need a guild in the way Jonathan is describing? I don't think so.