What Is the Primary Security Benefit of PoS over PoW regarding Network Upgrades?

In a PoS system, network upgrades can be implemented more smoothly and with stronger consensus because validators have a direct financial stake in the network's success. If a malicious fork is attempted, the community and honest validators can quickly align on the correct chain and punish the malicious actors via slashing.

In PoW, a minority of miners can continue to mine an old chain indefinitely, creating a persistent, less secure split.