It may be an overall increase in economic anxiety, even at the corporate level. At one time, AT&T could probably not imagine their status would ever really change; today, you'd be foolish to be running almost any company in the US economy and think that the company's position in 10 years is likely to be similar to the one it has today. Making longer term investments in employee skills is almost certainly concomittant with the idea of tackling their income needs/desires/wants, and that looks intimidating when you don't have faith that your company will still be growing 5 years from now.

Upper level is generally trying to figure out how to pad their golden parachute for the next quarter.

This is somewhat self-fulfilling is it not? I fear my valuable employee may leave, so to protect myself in this situation I withhold resources I could have granted them. Said employees later realize they could get better and leave.

It is in many cases. Short tenures often become normalized all the way around so companies tend to expect employees not to stick around too long and employees have a mindset that frequent job hunting is just what you do.