Tom absolutely was considered a great grappler who could take Gane down with ease. It's a huge part of why the lines were so lopsided even if the striking was maybe a coin toss, and why people had said for years Gane was "avoiding" him. There was supposed to be a huge disparity in their grappling abilities and that Tom could just take him down with ease if he couldn't also KO him.
Tom also shot immediately after setting it up with a leg kick, and drove Gane across the octagon. It wasn't half assed at all. He set set it up, tried for the entire octagon's length, and gave up when Gane defended it and shut him down.
Quit the revisionist history. His grappling being (somewhat) exposed doesn't mean this was what was thought at the time.