Politics like weather is local and same holds true for your experience at AT&T.
An incompetent manager/director/AVP/VP can make you despise this company even though the company itself is generous with pay and benefits.
An employee's experience with the company is LOCAL and bad management (which seems to be rampant) can and does make your life miserable.
It all boils down to a culture of fear and anxiety given how much an employee stands to lose if/when they're laid off. So everyone begins to act in their own self-interest because they realize getting the same pay in another company will be highly unlikely.
Hiring standards at other companies like Google are incredibly high compared to AT&T and there's a gigantic talent drain where a few companies seem to hoard the best and brightest.
So the OP is right in that the grass is definitely NOT greener so be careful what you wish for since you may get it!