Closed source is just such an inferior development model. Not that bad practices and stupid mistake would not happen in open source. It has happened and will certainly happen again.
But more eyes are always better. And people who value deep technical understanding over just making money are often found in an open source ecosystem. It is incredibly frustrating to have to work with black boxes like Windows where you have inferior choices to explore and fix things.
Obviously there are many decision makers who don't see this. So shops like Kaseya do unfortunately survive.
My company used to use Kaseya but luckily changed to a competitor a few years ago so dodged this particular bullet, but I’ve always said that these are extremely high value targets to hackers and I’m surprised there haven’t been more incidents like this - though Kaseya was also hacked to deploy crypto miners a few years ago too so this is not a one off event.
Given that the nature of RMM software specifically requires being able to push arbitrary code to large numbers of devices security SHOULD be paramount and having a respected open source solution for this would be ideal
If yes, then the damage should bankrupt them.