Firewalling customer support behind another company or division is okay, but at least make sure you have a parallel feedback mechanism to know how they're doing!
Social media support seems like the shitty version of this, but it's not rocket science to be able to regularly independently audit a random subset of issues by your CSR contractor. Internal audits have been standard practice in similar health care scenarios for decades.
As a result, for many companies obsessed with KPIs, the only KPI for customer support is "price". In that lens, they are optimizing.
Obviously this situation is awful for customers.
If you've got nice insulation from your customers, how do you even know what you built is working?
I've seen too many bizarre real-world failure cases and complex systems-on-systems to trust that my metrics are capturing everything that breaks.
But every thing with that is wrong. That part in particular "workers typically have very little authority to escalate or fix more complex issues" is a plain and straight refusal to solve any problem the company may cause.