Making games that are sub par, uninteresting which fail to sell is to blame. What they need is to get developers who could create something to will gain anticipation because of that, receive great reception. Alien: Isolation is a step in the right direction but they need to produce something that would be up there with games like GTA V and The Last of Us. A new IP from them woulld help.
Another thing they need to do is to stop taking really unnecessary risks with their main IP, Sonic and finally put a stop to the inconsistent quality of his games. SEGA are taking Sonic in a poor direction with Lost World and Boom. I thought Sonic had become good again after Colors and Generations why did they have to fuck it up. Just when you thought they have finally created a modern formula and style of gameplay for their games they had to throw it out of the window with Lost World. How the hell did they let Boom release in the quality it was in as well. SEGA and Sonic Team have to do a lot to put Sonic back on track. In all honestly the series needs at least five years without any games for people to recover and then reboot it and make it look like the definitive game in the series. It's the only to have get people to have faith in the blue blur again. (and don't do it like '06 did it)
If SEGA do these two things, then the company will be back on the map again and recover from the layoffs. Sadly I don't think they will, I still think they will milk sonic with games the fans didn't ask for and put out other games without catching people's eye. Deciding to go into the mobile industry is a sign of giving up. I so hope SEGA don't focus on cheap PC and mobile games and instead attempt to revive themselves but unfortunately it's looking like they will.
