Lockheed is indeed merged with the Martin Corporation and is today known as Lockheed Martin. The relatively poor sales of the TriStar led Lockheed to end commercial aircraft design and production (the civilian Hercules is merely a development of the military workhorse) but the plane remains an elegant bird with solid performance and excellent safety - no TriStar has ever been lost due to purely mechanical reasons. So Lockheed's tailoring of the type to the RB211, although the deathknell of the plane, was certainly an advantage in the sense that the plane and engine truly performed in an outstanding manner as a unit.
I doubt that Lockheed would ever return to commercial flying and today's twin craze will certainly put paid to any trijet development. Certainly trijets have no ETOPS issues but then, one must remember that engines available now are so much more powerful and reliable than those available 20-30 years ago that twins could virtually do anything that once required 3 engines. It is sad but do not expect to see any New Generation TriStars when the old fleet passes on.