This decision might be correct but the previous one was wrong. In his own words:

"I made the decision to significantly increase our investments. Unfortunately, this did not play out the way I expected."

So, keep him to downsize the company and replace him when it's time to start growing again?

It's evidently clear now, his "correct decision from a business point of view" to increase investments during Covid was wrong as they resulted in these 11,000 people being let go. I think the same could be said for the increased investment in metaverse, which I imagine is predicated on the prior large growth of people moving online during Covid, which is now returning to the mean.

I think their share price has taken strong corrections due to these decisions. I think that's an incentive for a board to take action?

(I'm purposefully ignoring the ouroborus that is Zuck's control of voting shares that protects him here.)

This decision is correct, given all the incorrect strategic decisions he made leading up to it. The markets have clearly lost a lot of confidence in his leadership, and I would have to imagine the remaining employees have too. Stepping down would be a drastic step, but merely stating “I take responsibility” is unlikely on its own to restore confidence in his ability to right the ship either.