I’ve run a game like that, and it worked well. The in-game lore was that everyone was part of a startup mercenary guild, and the adventure of the week was basically whichever characters had accepted that particular job posting. Nine players total, but we never had more than five at the table at the same time. It helped hand-wave away a lot of the “why is only half of the party here” stuff, because we could just say they were on other jobs, working on administrative stuff for the guild, or doing their own personal stuff.

Then the larger plot was largely focused on the intra-city politics that go into starting a new guild. All of the “you need to curry favor with a local powerful figure, because your guild needs something from them” type of stuff. The guild had taken out a rather large loan to get off the ground, so there was always some “enforcers will start breaking things if you stop making money” threat to keep the players focused.

And the individual players didn’t feel a ton of pressure to show up every week, which meant they were actually there because they wanted to be there.

Oh boy, playing RIFTS as my first go as a GM (aka DM) was how I learned to play by the rule of cool and come up with challenges/stories that weren't directly dependent on character power levels. So much fun to be had with a mix of MDC and SDC characters, dimension hopping, and I also loved reading the expansion books for the over the top flavor text and inspiration.

Tried out other games to reduce complexity but still kept at least one of the expansion books for inspiration.