Well, like NineLine said: it is a living company and a living game, and at the end of the day, someone needs to pay the bills to keep the power on in the office and put something to eat on the table.
Fixing bugs doesn't do that, in the current business model. New modules do. So they have to do both at once, there is just no way around that fact.
I, personally, am willing to accept that stuff will always be borked and broken in some way or another, unless anything changes about said situation. I am working in software development mysself, so to me that is a non-issue.
Also, I don't run a business myself, so I wouldn't suggest any other business model to them, anyway - but my gut says, that any other business model, with say "monthly costs" or similar will cause even more problems.