The thing about PC users and this doesn't just go for quest based mods this goes for everything, all pc mods are free. how many new companions have console users gotten? none how many companions can PC users get? over 300. How many new guns can console users get? maybe 4-5 guns that are the exact same copies of other guns but with a fancy name and higher stats per DLC. How many new guns can PC users get? over 19,000.
Those are just a couple of equivalencies, and that data came from fallout Nexus.
Modded content, especially when it comes to quests, is often not of the same quality as that of the game itself though. There are still very few decent quest mods for Fallout 3, and even fewer with voice acting. And they take a lot longer to make than DLCs from professional companies.
The PC version does not have these benefits out of the box, they are made by fans. Just because fans are willing to create things for the game, doesn't mean PC users shouldn't get the same official content.
Also basing mod statistics on the number of files on Nexus is hardly accurate. There aren't 300 real companion mods, just as there aren't 300 quest mods. Or 19,000 weapons.