I'm sorry, I highly disagree.
The Doom comparison doesn't stand because Gzdoom isn't classic Doom anymore, it's a modern engine and has to be treated as such, a 760 can barely run anything nowadays, and so it can barely run Gzdoom like any other modern program or game, it's a ship of theseus situation, there's barely anything that resembles classic Doom code and rendering wise, and it's fair because atleast for me, making vanilla or classic Doom experiences is not what i'm looking for, I'm more into making new games with Doom as a base.
If a PC can't handle Gzdoom, it's not because it's bloated, it's because it's time to upgrade. In fact I'd say the only reason why there's a bit of bloat in the engine is because it has to keep a lot of legacy support not to break things with much older projects, VKDoom, a fork of Gzdoom, drops that and as a result has a much faster rendering pipeline, especially regarding shaders and dynamic lights.