I found this to be true, too. Though with a caveat, a lot of thrift stores around here don't have many ties. Ever. Maybe I don't go often enough, but if I go to the communities where you're more likely to see people who might wear nicer clothing they appear more often. There are a couple of gems, like the charity shop where I got my Hermes, but yeah, even there it's hit and miss because a few folks down in San Diego farm the same thrift stores to sell on ebay.Most thrift stores price ties at $1-2. I've found a few 7 folds that were very nice--and if I hadn't looked that morning they would have likely been on eBay that afternoon for twenty times as much.
And for pocket squares, I have grabbed them for as cheap as $1 a pop at thrift stores. They don't always know what they are so you'll find a fancy silk hand-rolled edge square in a pile of cotton bandanas or women's scarves.
My last ebay score was 9 squares for $35. I was looking for something and saw one of the lot I liked. Bad pics, but 100% rating so... I really don't want most of them, but they'll almost all be used be me or someone. The silk ones all have hand rolled edges, like brand name squares listing for 10x that price new. And except for one (not pictured) with a stain that the seller noted they all look nearly new. I'll definitely use one or two, maybe let my friend take any he wants to wear.