They make enough money in between selling the tool and Apple patching the exploit to make it worthy, not to mention the amount of people who don’t do updates meaning the tool is still effective some of the time.

Then the find/buy a new exploit and do it again.

I think the assumption is that if they have the capability to create this exploit chain, they also likely have the capability to develop others (and possibly have others waiting to deploy if these are discovered and patched).

It's the same with any of these hacking technology companies, they have to keep moving at the very edge of what is possible.

Fixes it?

Apple could indeed fix some CVEs that they know about but every new OS/app/library release has the potential to introduce new CVEs that hackers can exploit.

It's a moving target indeed but due to the increased complexity and questionable quality of modern software there's no way they're going out of business, quite the contrary.