Kalinske re-tooled Sonic and gave him his attitude. Sonic did far better in the US and Europe than it ever did in Japan, and Japan's initial vision for Sonic was cringeworthy. Sonic in a rock band, with a human Betty Boop style blonde pinup doll called Madonna as his girlfriend. Sega CEO Hayao Nakayama would defer to Tom on all major decisions, and SEGA of Japan eventually got sick of hearing about the favored Westerner.
After a good number of years where SEGA Of America's president Tom Kalinske lead SEGA to the promise land, Sega CEO Hayao Nakayama suddenly stopped listening to him and made ALL the wrong moves. After mandating that 32X HAD TO happen, he then foisted it off onto SOA as thought it was their idea whilst he went and planned the Saturn.
Sega Of Japan's Board Of Directors scuppered plans to work with SONY on the machine that would become the PlayStation after Nintendo screwed Sony over. Scuppered plans to work with Silicon Graphics, who went on to produce the 3D visuals for the N64. SEGA's bad press around the time of the 32X/Saturn was so bad, Bandai's employee's blocked a buyout of Bandai by SEGA, a move which would have given SEGA ownership over Bandai's properties (Kamen Rider, Sailor Moon, Power Rangers), additional income from Bandai's themeparks, and income from Bandai's new Tamagochi fad item.
Then, Sega Of Japan REPEATED the same mistake with the 32X, pre-emptively killing off Saturn in favor of DreamCast when Saturn still had some legs left just like it had done for CD/32X for the Saturn. I 'think' SEGA did it a 3rd time with the DreamCast, where it's arguable that it could have limped along until all those DreamCast sequels that eventually wound up on Xbox 1 released on DC, but chose not to.
