So the best they can do is use the same engine for 3 games?.
The engine doesn't break because it's complex, it breaks because it is poorly coded.
Oblivion, FO3 and FNV all use the same engine.
Granted, using a new engine introduces more bugs, but when this old engine they are using has the same bugs in each new game they make, it's about time to get a new engine.
Not just that, but the graphics quality would be much better if Bethesda didn't recycle the same engine for 3 games.
I hope TES V will be epic, but I can't see Bethesda changing their engine, and it will severely hurt the potential of TES V. But if they do, it will be the best elder scrolls game yet.
What do you mean by new engine? Do you want them to abandon Gamebryo all together? I'm not quite sure, but I'll pretend as if that's what you mean.
If you are going to compare Oblivion with NV you might as well throw in Morrowind since that is along the same lines of what you're doing. The only major engine change since Morrowind was the graphical and some of the physics changes between TES: III and TES: IV. Ever since then the engine has slowly been upgraded with newer modifications, code changes, optimizations etc. You don't suddenly change everything about your game in between one game, it takes a number of games, though I do predict that TES: V will see some significant changes in engine coding and optimization from Oblivion.
And please don't drag NV into this discussion, NV is a spin-off of the Fallout series, meaning it's engine is basically Fallout 3 plus some extra stuff, plus NV doesn't even count among the games that Beth
develops so it's really a
similar engine for 2 games. Oblivion's engine is not identical to Fallout 3's, it is in fact much less optimized I can personally see the difference in the two when running F3 and Oblivion on my computer, F3 definitely lags less.
(I'm not sure, but I do recall hearing somewhere that Fallout 3's source code was much larger than Oblivion's, meaning more commands and such, this is in brackets because I'm not quite sure whether this is true or not)
Fallout 3's engine was not expected to have a major jump from Oblivion because it was already a major jump from Fallout 2. Plus the team likely did not have to make any major engine re-vamps while making the game in the first place.
EDIT: I'd also like to re-iterate the words of these two wise forumers who answered this question before:
They didn't use it for New Vegas because they didn't have time and resources for that. A LOT of stuff was built on top of Gamebryo to end up with Oblivion. After that they modified that engine to make the Fallout 3 engine. That was a lot of work. When they brought on Obsidian to make New Vegas they weren't in a position to do another 4-year development cycle for it...they're probably working on TESV. So, they gave Obsidian their dev tools, assigned some of their own staff to help out and manage QA, and said, "here's this...be done before the holiday season in 2010...go." There's no way they had time to overhaul the engine based on the new version of Gamebryo. They'll probably do something like that for TESV and Fallout 4, though.
To add to Softnerd's post, Gamebryo is specifically designed to be augmented and changed by the developer using it. It's primarily a graphics engine, the other aspects are rudimentary or nonexistant, so developers can easily mold it to fit their needs. This is great for Bethesda since it allows them to create an engine that supports huge open-ended worlds with lots of NPCs and clutter, requirements most engines don't need to meet. With a fully developed engine Bethesda would need to strip out more components in order to rebuild it to their specifications which is time-consuming and easily introduces problems.