I think Very Good is a bit of a stretch. Well, we are dealing with subjective terms, so it really is just where you set the bar.
Gartner was primarily a goalscorer. He wasn't known for his playmaking, physical presense of defensive play. Over the course of his career, Gartner was rarely (if ever?) one of the top-5 goal scorers in a season. He rarely cracked the top-10. He was consistantly in the teens at the aspect that defined him.
What makes Gartner noteworthy is the length of his career. While noteworthy, I don't see that as a Hall of Fame credential. Kudos on avoiding injury and staying fit enough to last 18 seasons, but what he did during those 18 seasons is of more importance. In those 18 seasons, he was never a top player at his position and as an offensively minded player, rarely cracked the top-10.
As for Osgood and Burke, I think they are even less qualified than Gartner. Neither should ever get a sniff of the Hall. However, they fit the criteria given. Only thing they had in common with Gartner is long careers.