One of the earlier consoles, can't remember which one, but it ended up flopping pretty hard. So they rushed out the next console. They also sank a lot of money on different kinds of gadgets to play with, i think one of em was motion control. Anyway the marketing at the time cost them a LOT of money, which brings us to the end console, the Dreamcast.
The Dreamcast was amazing. It wasn't the best graphically, but it had a good number of games (Sonic Adventure and Powerstone.) The issue was they were losing money with every console sale and pirated copies of games became so common that it was easier to find than legitimate ones. It's really a shame, the Dreamcast was one of my fav consoles (I still have mine.)
Sega was one of the leading console designers around the 80's, they went toe to toe with Nintendo, really wish they were still in the market