Airbnb is a great example of both. If you call tech support and get India, hang up. If you're lucky they're useless. If you're unlucky, they're going against your direct command and contacting the drug dealers in your house about a complaint. Contrast that to reaching one of the many on-shore agents who do their jobs well. One call, one or two people max and the issue is mostly resolved.

I've got no idea what the cause is. It's probably a mix of poor management, ineffective metrics, low salaries and a work culture in India which isn't synonymous with quality. The bottom line is, even the same company can be doing support wonderfully and terribly at the same time.