OG Doom has a couple of things going for it.
1) The 2.5D engine helped it escape the uncanny 3D hell that post-Doom FPSes had. Quake is the first truly 3D engine and it showed massively. Everything from the crude architecture to the blocky 3D models looks incredibly dated. By contrast, Doom was naturally unrealistic, with the whole cartoony aesthetic that allowed you to suspend disbelief much more. Also, the Doom sprites aged much better. (I am of the opinion almost all sprite-based games aged much better than their later counterpart.)
2) Doom had just enough variety of weapons and monsters to keep things fresh, without being overwhelming. And mixing and matching them continues to provide a challenge to this day.
3) The modding community was much more robust than either Quake's or Wolf 3D due to sheer ease of swapping in PWADs. To this day, I don't think any other game replicated this, with the exception of Half-Life and their innumerable goldsrc mods, and Warcraft III TFT with similar custom map shenanigans. It's telling that these two are also very much enduring to this day as well.