What, in the sense that sega was making a new home computer for the market, but switched to console development as soon as they heard about the famicom’s impending release? That culminated in the s-1000, which used cartridges, but later shifted to cards, like the turbografx-16/pc engine and the s-1000’s third model was just the earlier Japanese version of the master system, where it was a big flop, but somehow still got localised, in the form of the master system, where nonetheless, it was still a flop, albeit successful in Europe and South America(essentially just Brazil) as you said. Sega saw the issues in the master system and fixed them with some next-gen elements to make the Genesis. Unfortunately, sega probably went delusional with the successes of the genesis, and released the Saturn with some of the issues the master system had, even the Dreamcast released later wouldn’t be safe from the failures that the Saturn had suffered from, and carried on.