Memory is short on the internet. Reddit are hoping for this to blow over "quickly" (i.e. in a month or two) because they know the bulk of their users will continue to show up (out of inertia or a lack of viable alternatives). If they can keep the front page showing decent posts, they think they'll make it through.
I think the knock-on effects of losing mods and "power users" will take some time to play out. The real long term effects won't be known until it becomes clear that the loss of those key users has effected the quality of the posts and therefor usage by your "average Redditor."
It’s already happened!
THREE TIMES
2023: https://www.axios.com/local/new-orleans/2023/06/16/louisiana-cyberattack-dmv-moveit
2019: https://arstechnica.com/information-technology/2019/11/hackers-paradise-louisianas-ransomware-disaster-far-from-over/
2016: https://www.hackread.com/hacker-selling-louisiana-drivers-licence-database/