It seems that a lot of companies are doing this. I called AT+T about a year ago to question something on my bill. Was on hold for 2 hours, with that annoying recording assuring me that someone will get to me soon, but maybe I should call back on a lower volume day.
I ended up dialing an AT+T operator, who hooked me up to a customer service rep immediately. They didn't understand that I wanted to cancel my Long Distance with them because waiting 2 hours on hold was totally unacceptable. Then they try to bargain with you, offering you something like 3 cents/minute long distance (which I'm sure will get jacked back up to 10 cents/minute plus other fees within a couple months).. Anyhow, told them I wouldn't stay with them even if their service was free. Then they threatened me with a disconnect fee.. Told them I didn't care.
Anyhow, the point is that companies seem to be using the "infinite hold" strategy DELIBERATELY in order to try to get you to give up. After all, there were reps available to answer my call immediately when I called the AT+T operator.