Lots of people seem unclear on what actually happens during a writer's strike not just with the WGA but with ongoing productions. Here's a quick thread on one of the films that was affected the most by the 2007-2008 WGA strike - Quantum of Solace.

Background on the 2007-2008 WGA strike.
This went from November 5, 2007, to February 12, 2008 (100 days). Some of the key issues were DVD residuals and if writers for reality shows & animation should be in the guild.
Its biggest effect was setting WGA standards for all streamers.

Writing on a sequel to Casino Royale began in 2005 with the same team from that film.
While Casino Royale is acclaimed as an iconic, modern take on Bond, Quantum is... hard to remember.
Most people now (even fans) have trouble describing what the plot was.

In 2006, Quantum was announced for a May 2008 release but the script still wasn't there. The original director Roger Michell left the production due to script issues.
Quantum's doom was in meeting deadlines and the WGA strike made new deadlines of its own.

The shooting draft for Quantum of Solace was completed two hours before the strike went into effect. This meant the film could go into production with a script in hand but no rewrites could be done on it by a writer.

"We had the bare bones of a script and then there was a writers' strike and there was nothing we could do. We couldn't employ a writer to finish it. I say to myself, 'Never again', but who knows? There was me trying to rewrite scenes—and a writer I am not".
- Daniel Craig

The Quantum script was never as far along as it needed to be and the original hope before the strike was likely that it would "find itself during production."
With no writer on set, the only ones allowed to adjust the script were Craig and director Marc Forster.

Many of your favorite movie moments were written or adjusted by a writer the very day the actors performed the lines. When you watch Quantum, you see a film missing part of the filmmaking process. Casino Royale feels planned but spontaneous, Quantum feels rigid but messy.

When the strike did end, writer Joshua Zetumer was brought on (based on a spec script) during filming but the damage had been done. He inherited a mess and it become more about an onset writer working around this chaos that couldn't be ignored.

Quantum of Solace is ambitious, has some great Bond moments... but still the plot is lost on even the biggest Bond fan. So what could have happened differently?
It's easy enough to say "delay" but that's up to the studio and it was already delayed half a year.

A lot of writers take joy in exploring "Here's what I would have done differently with this troubled production" but there's no advice for Quantum. The studio was not going to delay that movie. There needed to be a writer present to guide the story and that happened too late.

It serves as a cautionary tale on the importance of having a writer every step of the way. That strike is long done and a new one begins now, but Bond fans will forever watch Quantum of Solace and say "Something is missing."
Writers can't afford to be missed.

Holding up a picket sign that reads "Quantum of So-Low pay" at a rally and verbally explaining the joke to every single person who makes eye contact