Everyone has a job to do, and I'm sure that some sort of a bug tracker is attainable for everyone by now, it's not a company DNA thing, you allocate enough resources to something then you can adequately support it.
Customer service is everyone's job because without customers you don't have a job.
Your backend developers shouldn't be answering phone calls from customers. That's the job of the helpdesk. But if the helpdesk doesn't know how to fix a problem, they should forward the call or the ticket to the developer. If something is messed up in the database, the helpdesk should have the ability to put the customer on hold, call the developer, and have them make the required change. If the documentation doesn't match reality, the helpdesk should have the power to get the developers to update the documentation. The helpdesk should be analyzing tickets and sending reports to development teams with the mindset that it is the responsibility and the expectation of the development team to make sure these calls stop happening, or that the helpdesk is empowered to resolve them without escalating a ticket.
That is a culture where customer support is everyone's job. If the development team is under no obligation to respond to ticket escalations, that is a toxic support environment. If development is under no obligation to reduce the helpdesk's call volume, that is a toxic support environment. If there is no helpdesk to call, or the helpdesk you've called has no direct line of communication with all of the supporting teams across the entire company no matter their role or function, that is a toxic support environment.
In every sensible development environment I've encountered there is a wall between the developers and the rest of of the company: their manager, who's responsibilities include shielding their team members from outside bullshit + the product owner who is the one collecting feedback / feature requests from other teams and prioritizes their requests according to the companies goals (which can of course include "build a user-friendly product").
In a system where there is direct line between the development team and other teams, most of the times the developers will only be able to get very little work done due to constant interruption, and/or they will end up spending most of the time fullfilling the requests by the people who cry the loudest, regardless if that's in the companies overall best interest not.
I'm talking about "your product documentation says to check the box on the third page, but there are only two pages". If the response is "I'm sorry our developers are too busy getting work done to be constantly interrupted", how many customers are you keeping?
I'm talking about "I purchased your product but it redirected me to something called http://localhost:3214/test/test_page.html". If the response is "Hi, I'm the manager who is shielding my employees from your bullshit" yeah you get the idea.
These are things an outsourced helpdesk (or even an in-house helpdesk) can't fix. But they are problems that real customers are having right now. Maybe it sounds like a horrible work environment to some people. To me it sounds like absolute bare minimum customer support.
Unless you are running a business where each customer pays a relatively big chunck of money (I'd say enough to employ a single developer), you always have to run the numbers, no matter if it is a feature request or a "holy shit" bug.