A gatekeeper is expected to loose to the best contenders when they step up. A policeman is expected to beat them and keep them from the champion.
Quite the opposite realy. He wen't into a fight with anybody expecting to win it, but beating him did not offer rewards comensurate to the risk. More a highway to oblivion.
A "gatekeeper" is a more serious challenge than a "journeyman." Edison Miranda would be a pretty good example of a gatekeeper. Quick Tillis, by the time he fought Holyfield, was a journeyman. See the difference? A policeman is not a category -he's an individual. He can be a gatekeeper too, but in his role as policeman he is usually a stable mate to a champion or name fighter and provides protection so to speak by facing certain potential challengers, knowingly or not.
Gene Burton was also seen as a "policeman" for Ray Robinson at the time. He only fought his stablemate Robinson in boxing exhibitions, never receiving an official match against the man. Took on a lot of tough guys and had a fine run in the late 1940's. Jerry Quarry is another. He especially eliminated Lyle, Foster and Shavers from contention for Frazier's title.
But without eliminating a single potential threat to the title in his entire career wasn't big cat williams only a "highway to oblivion" for journeymen outside of contender status?
People with something to loose in terms of standing, and or realistic aspirations to championship status, simply didn't fight him. This limited his career progression at certain times. I don't think that anybody other than Liston would have seen him as a stepping stone to bigger things. Liston was willing to fight him because he had problems of his own. Once Liston held the title, he seems to have planned to use Williams as a roadblock.
Williams was a headliner who was popular in that he spectacularly knocked out journeymen. He wasn’t going anywhere because he was a good enough attraction in Miami and Texas for doing just this. when he went to new York or Philadelphia he’d get beat. 95% of williams's fights were in Texas and Florida as the "house fighter". Nobody else wanted to fight an unrated big fish in a small pond. Liston was the next competative match williams was in after the satterfeild fight. Liston was already considered beter than williams since he knocked out 34-15 frankie daniels in one round and williams struggled over the distance with frankie twice already. maybe sonnys backers felt Liston could make his name in miami and texas off the back of williams because he couldnt fight in newyork? He gave Liston a good fight, maybe liston just thought williams was good enough to fight more good fighters rather than the "profesional opponents" and stunt men the cat was fighting in texas? I still dont see how williams had anything more to offer than worthy rivals machen, folly, ingo and patterson?