Ady Stokes absolutely nails a reason why whole team responsibility matters, even for those that are skeptical of the reality of making it happen and the use of it as a term.
"Probably the most important one is having a whole team responsibility. Some people aren't keen on using that type of language. If everybody's responsible for quality, nobody's responsible for quality. I understand that argument. But if the whole team is accountable for what they produce at the end, the whole team is invested. And the way you do that is you make sure everybody is on the same page, everybody has an understanding ... everybody can have an input."
Ady shares this in the Software Quality Engineering Certificate (SQEC), Module 6, Lesson 7: Usability and accessibility in a Quality Engineering context.
How about you? What's your take on why whole team responsibility matters?