The first, second and third reason is piss poor senior management. You can insource, outsource or have both to your hearts content but if you have a management layer that 1) dont listen to their customers 2) dont take accountability or responsibility for their function, you get this mess further down the chain.
I used to run customer service functions and I can tell you that good ones are constantly monitored by management. response times (on the phone) abandon rates (the number of callers hanging up without being answered) customer satisfaction (little call surveys) productivity, and on and on. Those numbers are monitored by the minute by good management and when phone queues get long, remedial action taken, if satisfaction dips, remedial action taken. Management should be actively listening to a sample of service calls made each day and feeding back both the good and the bad to agents. Not only is this stuff managed actively but the daily results will be fed to senior management who should be interrogating any worrying trends and taking remedial action. It doesn't matter if its outsourced, your contract specifies what service levels you want and you are still actively monitoring that you are getting that.
Its not that difficult but it needs forensic management, attention to detail and people who absolutely care about customers. Everything they do re the design and implementation of processes, scripts, new systems, everything, top to bottom should be pointed at service excellence. Do that and the service you provide is fucking exceptional and that is what any good organisation should want. Everyone involved in delivery of customer service should be paid and bonused around customer satisfaction levels.
Sorry to go on a rant but I have lived and breathed this stuff for most of my career.
It makes me so angry that something that I truly love (the club) can be so fucking abject, uncaring and unprofessional with this customer facing element.