The lineup stayed the same, but the roles shifted.

It didn’t change at all — same four guys: Gilmour, Waters, Wright, Mason. Between ‘Meddle’ (1971) and ‘Dark Side of the Moon’ (1973), the band didn’t swap out members. What changed was how they worked together.

On ‘Meddle’, they were still figuring out their post-Syd sound. David Gilmour was co-writing a lot, and the band operated more collectively. By ‘Dark Side’, Roger Waters had taken over as the primary lyricist and conceptual driver. That’s the real shift — not a lineup change, but a power shift.

They did bring in session players (Dick Parry on sax, Clare Torry on vocals), but those were additions, not replacements. The core never changed.

The real change was in the band’s chemistry and direction, not the membership.