Lvl 78 just tried trading for the first time today, not one response all day!

As far as I know this is somewhat intended behavior -- I'm not saying desired behavior -- but GGG is aware of the issue and based on my understanding of GGG's stance they accept this as collateral damage and in PoE1 have not been particularly receptive about making changes.

Note: I believe GGG did indicate that if they "fixed" the issue there would be a corresponding item / currency nerf because GGG is of the opinion that the easier it is to trade the more scarce items [worth trading for] need to be.