i can give my insight on seo/expired domains auctions most of the time they go unnoticed because the niche is pretty small and the cost of the filtering tools is way too high for average individuals to afford so you will see the same couple of companies and high value individuals participate in these auctions time and time again with no exposure!
now for the auctions with no bidders at times it is just the wrong timing for the seller to list for example my friend listed a domain last month but it was the holidays no one was participating the domain is worth at least 1k for the SEO value but it didn't sell because no one was working at that time other things that play a big role here is where you list it if i list an seo domain at sedo of course i won't get any bidders for the fact that most buyers at SEDO are not looking for that. that's just my personal experience with the type of domains i deal with