The author says:

• what makes an effective UX team is the completeness of the skillset across all the members.
• The roles of individuals are secondary a team with generalists will always be more flexible than a team of specialists.

Specialists help when the local economic conditions support their being there. Yet, specialists have general knowledge, so they can be flexible and interact with the rest of the team in a productive manner.

Ideal UX Team Makeup: Specialists, Generalists, or Compartmentalists