This seems to be a tell-tale sign of a niche that is too competitive. Doing allintitle searches gives you results that may be too specific. Let's say you find a longtail keyword with 75 monthly searches and hardly any competition. You write a highly optimised post for that longtail, but those 75 searches/mo return 21 million web pages. How in the hell are you going to beat out 21 million results. Is it better to search that longtail keyphrase naturally and look at the results from that? Maybe try to get as low a number as possible for natural search results, then go from there?