No, it doesn't. Herv?Caen became top dog of Interplay and he decided to focus on the console market rather than the PC market and cancelled Fallout Van Buren in order to focus resources and budget on Fallout: Brotherhood Of Steel. FBOS is so bad that it isn't even considered a Fallout game by just about every single fan out there as well as Bethesda because of how much it contradicted with Fallout's design and previously established lore. It didn't help that the game was a failure on its own merits either. So guess what happened? It tanked. And because of that and other poor management decisions Black Isle was shut down and Interplay never really recovered as a game studio.
It didn't have anything at all to do about Fallout itself. It had to do with poor management. Cancelling a sequel to a series with a lot of support of its fan-base which was quite far into development in order to create a completely new spin-off for the series that went completely against what that fan-base wanted out of Fallout just so that Interplay could weasel its way into the console market is poor management.
As to why Bethesda managed to do what Interplay couldn't, considering that Fallout 3 is not what the original fan-base wanted out of a Fallout game and is a game targeted towards a console audience, is because they had their own fan-base to cater to. They created a game they knew would sell by using the development techniques that worked for Oblivion. They also had better marketing and quite frankly Fallout 3 is a fun game (on its own merits) and while it changes a lot of mechanics and isn't exactly too respectful of the lore it didn't mess up as badly as FBOS did.
If the old Fallout's were doomed to fail because times where changing then there wouldn't be any turn-based isometric cRPG's developed in this time and age. But guess what? There are. X-COM, Wasteland, Torment, Divinity Original Sin, Underrail, Expeditions Conquistador, Shadowrun Returns, Dead State. You know why they stopped being developed back in the day? Because the publishers didn't think they'd sell. Now that developers have other means of getting funding they are creating the kind of games they always wanted to create since they don't have to rely on publishers backing them. And some of them were even able to persuade publishers to give them a shot at creating something more old-school, such as X-COM.
Do you really think that if they had had this kind of funding method back then that they would not have used it to create cRPG's like they wanted to?
Fallout was not the problem, it has never been the problem.
Herv?Caen's management decisions was the problem.
Well, personally I just don't want a "giant" sandbox map because no matter what Bethesda does they have to scale everything down and I'd much more prefer a map node system where there are about a dozen to 20 different maps that are the size of the DLC maps. Cities would be designed like The Pitt (though change the Steelyard area into a civlized area) and exploration areas would be designed like Zion or Point Lookout. And then there'd be about 50+ locations you can find on the overworld map that are like Satellite Array Station, a small outdoor area which leads you into a dungeon. The rest of the gameplay can stay largely the same (first person, real time, shooter-esque), I just don't think a "giant" (it's not that giant...) sandbox map does Fallout justice.