Why even bother?

I’ve been in the market for a specific speaker. Twice I’ve responded to ads.

The 1st one: We were agreed on price and that I would drive (about 6 hours each way) to get them. Just a matter of timing. They’ve been packed up for some time apparently. On April 27th, I emailed, simply asking if he’s run them lately just to make sure they are ok. As of today, May 10, no reply. This is even after a phone conversation a few weeks ago. Oddly, he has good feedback. The ad was on the "other" site but feedback here was good also.

The second was from just a few days ago. I responded to the as right after it was posted. I asked the usual questions (age..how many owners, etc.) No response. After a couple of days, I resent the questions. So far, nothing.

So....WHY do people go to the trouble of placing ads and then not responding? It’s really baffling.