I wonder why folks with items in TP don't respond

There have been a handful of items that folks have on TP for more than can be offered with NP, and I NM them saying I'd like to buy. I almost never get a response and it seems like the person is active and will even re-post the item on TP.

I didn't ever expect to beg people to take my money. Does anyone else experience? Anyone have any ideas why no response?