This would be true if you could build bases anywhere, but you can't. You build bases on predetermined lots that are, in fact, optimized in advance through clever occlusion techniques. Gamebryo also uses "interior cells" for various interior spaces, which means the rest of the open world isn't rendered when you're inside. And these "cells" aren't truly elaborate interiors with huge draw distances. Often they're warrens of offices and small rooms, all of which could benefit from extremely simple optimization techniques. The level of fidelity that the engine is capable of delivering (based on my experience with the Creation Kit) stands in sharp contrast to what Bethesda actually presents. I think one explanation for why interiors aren't substantially prettier given the performance advantages of "cells" has to do with a certain design philosophy.
Yeah, I didn't touch on interiors since they are undoubtedly a much, much less resource intensive in their engine and for examply could be benefit from a some pre-baked routines, better occlusion culling, lighting setups and more. I feel the fidelity they are delivering is much more constrained by production resources rather than anything else, which hopefully they have considerably improved since they have been quite active in hiring level designers.
That said, they are also limited at least partly by the same constraints. Props have to be individual gameobjects and draw calls, there's little room for pre-baking due to the nature of modules (and it would add quite a bit more complexity to modding).
It's a much more of a general problem with the exterior cells where the game can't use many of the technique used by W3 or GTA V, mostly due to gameobject handling and the general mod support (which adds a huge, complex overhead in to the production, engine and graphics). For example Umbra would not realistically be feasible for them, nor some of the lodding methods of GTA V (which are based on a very static environment cells and lots of single draw call of lod models).
Bethesda must target some minimum level of fidelity across interiors and exteriors in order to avoid the chore of developing high quality and low quality assets for two different spaces. That makes sense if time and resources are limited. Yet even if that were the case, it still doesn't excuse the lazy, bland lighting design for offices, vaults, etc. where you have complete control over the player's line of sight.
Yup, that is very much the core reason of not only the general level of polish in interior cells (as in there lots of room for improvements) as well as for example texture authoring. A general workflow is required for the consistent level of detail and performance most cells have (not to mention the production aspect, but that could spin off a whole another post from me, and I simply don't have the time right now), but also the reason why they definitely show the compromises.
That makes no sense what so ever. Sure modding is a big part of bethesda games. But to have a game in production for over 4 years and have, competition in Western made RPG's like The witcher 3, and dragon age show a better use of revision in engines to me is slap int he face.
No, for any developer with proficiency, it makes absolute perfect sense. That modding adds a massive overhead to the whole game, from production to rendering thread to game logic thread to texture authoring to shaders to everything. I am fully aware that the Witcher 3 for example has modding tools, but they are not nearly as expansive nor was the tools for TW2 in any way near as useable as Creation Kit for example. That usability comes at cost when you need performance, as it means less pre-baking, less control over the individual situation, more overhead in object logic etc.
Again though, none of the above means that I should be happy with low-poly props, texture seaming, material lighting, SSAO or others. It's just a part of the whole, complex function and I do wish that we had gotten more, but I also realize that what they have done so far is in anyway a small effor or investment, it should be obvious that their rendering pipeline has gone through some massive changes.