They are a great place to start. They're something everyone should be doing.
I don't disagree with you on SEO either. I have the #1 rank in 19 of the cities I'm in. Top 3 in most of the others. Then a few straglers in towns I wanted to see if I could rank in for fun... Like Hawaii. I've had over 1100 leads come through my carrot site.
I have an issue with making blanket statements like something doesn't work or is a bad idea when every major player in the country is using it consistently to purchase deals.
The original poster asked if it's still working. The answer is yes. It may not be your favorite flavor. But it is working.
Comically we have actually seen an increase in response and conversion the past year or so as more folks have moved to cold calling, bandit signs, text blasting, PPC, etc.
Last year we had 1,146 leads come in to my office. 60% came from direct mail. 40% came through my carrot site however according to Google Tag Manager/analytics more than half of those came from Direct Mail with our brand printed on it. Another 25% of the lead flow came from PPC, GDN, and Social Media.
Moral of the story: If you want to do a deal a month or so you can pick one niche' and just run with it. If you want to do 50+ you're going to have to diversify responsibly.