They did care, just too late to do anything about it. Initial MT always felt farmed out to DGP to me. Chuck Gannon was an attempt to impose some control but I don't think he really grasped what the game was about. Dave Nilsen, for all the vitriol regarding him, cared for Traveller quite a lot. And by the end, rightly or wrongly, it was MT's "brokeness" that led to the advent of TNE.
MT WAS farmed out to DGP. As much as I loved DGP and their products, people from the "loosey, goosey" school of gaming have no damned business writing or rewriting the rules. Anything that they were not interested in was done half-assed, i.e. ship design. Look at the gyrations needed to recreate any CT ship in MT.
As far as GDW not caring about MT I give the following:
1. Production schedule:
1987 - Referee's Manual, Player's Manual, Imperial Encyclopedia, ($30)
1988 - Rebellion Sourcebook, Referee's Companion ($20)
1989 - COACC ($10)
1990 - Fighting Ships of the Shattered Imperium, Knightfall ($20)
1991 - Hard Times ($12)
1992 - Astrogator's Guide to the Diaspora, Assignment Vigilante, Arrival Vengeance ($17)
Doesn't look like it's adding very much to GDW's bottom line does it?
2. Have you looked at Don Mckinney's errata? 57 single spaced pages of errata tells me that no one at GDW was minding the store.
3. Fighting Ships of the Shattered Imperium - enuff said.
4. Look at the decline of Traveller articles in Challenge Magazine.
5. Rules sets published in 1987 - 1st Adventure published - 1990 (by Joe Fugate of DGP), 1st Adventure published by GDW staff 1991 - only MT item published by GDW that year.
TNE came about because no one at GDW was interested in the MT milleu. TNE was based on the internal gamesystem that GDW was playing at the time. GDW was under the delusion that everyone would just go out and learn a new gamesystem just because the name TRAVELLER was slapped on top of it. Of course, GDW wasn't the only game company doing this. At that time, it seemed as if EVERYONE was re-writing their core rule books and expecting everyone to continue to repurchase everything they already owned, AKA, the SQUAD LEADER fallacy.
In addition, Marc Miller felt that the only way to regain control of the OTU was to blow it up & start all over. In doing so, he chased a lot of people off. I know that I had absolutely no interest in wiping out 13 years of playing experience & starting all over. Especially after seeing how GDW "supported" MT.
Of course, to this day, Marc & Loren still feel that they made the right decision to blow up the universe. It is interesting to note that after TNE, each version of traveller went back in time. From where I sit, doesn't appear that anyone is interested in the post 1120 traveller universe.