As ray said, it makes a lot of business sense. I haven't kept up with them over the years, but it's my understanding that most of the decent Lucasarts games have been developed by others, with Lucasarts serving as a publisher. And Disney already has their own game publishing imprint, so no big deal there (well, other than to the folks who lost jobs).
But back in the day, for PC gaming, Lucasarts was one of the best. Lots of fond memories of the X-wing/Tie Fighter games, and of course the adventure games (Monkey Island, Sam & Max, Grim Fandango, etc). These days some of their properties (and some of the original developers) have been snagged by Telltale Games. The new Sam & Max games have been great. And not Lucasarts (but adventure game related) they recently got the rights to do a new King's Quest game. These days that's definitely niche gaming, but in the 90s that was a very popular style of game, and Lucasarts were at the front of the pack.
So makes a lot of sense, but can't help but feel a little sad.