My guess is that it's going to turn out that free returns drives a large number of sales, and removing it is a mistake. A lot of online shopping can be impulsive, and the knowledge that any impulse is effectively permanent will change habits in a way that I believe will reduce sales dramatically. Especially given how places like Amazon don't always send you want you think you ordered!
I have to say that I don't find the tightening of return policies too onerous. I just don't want the pendulum to swing too far the other way where it's nearly impossible to return anything.
The pendulum has already swung so far with free deliveries that I will take the paid option every time.
Free returns was always a bad idea that is also now approaching its ultimate conclusion.