The Deadlift: Not Great For Building Mass
Sure, it's obviously a great movement to build and demonstrate overall strength. And before you get "triggered" and start throwing a hissy fit, I didn't say you can't build mass with the deadlift. Clearly you can. But the deadlift alone isn't a great mass-building movement.
The deadlift, performed correctly, starts with a push off the floor by the legs and is followed by the "pull" portion once the bar gets above the knee. You aren't really pulling the weight off the floor unless you're doing a stiff-legged deadlift, or unless you're deadlifting improperly.
Most of the musculature doing the work in the deadlift is in an isometric/static position. But the movements that offer loading with a significant deal of stretch in the eccentric portion offer a greater potential for growth. Think incline dumbbell curls, pullovers, sissy squats, deficit stiff-legged deadlifts, chins, dips, etc.
The deadlift starts from the floor so there's no eccentric (negative) when done in competition style. No eccentric component, little growth. Here's what eccentric specialist Jonathan Mike, PhD, said about eccentric loading and the deadlift:
"There's very little eccentric loading and activity, and very little TUT (time under tension) especially if you count the time the muscles are actually producing a lot of force, not the time that the lift lasts."
Make note of his comment regarding TUT because it's important. Even if you perform a deadlift where it takes 5 seconds to complete the concentric or lifting portion, there are so many muscles involved that the TUT is dispersed very broadly, so much so that none of them get a ton of direct stimulation.
Add in the fact that the only significant joint movement comes from a slight amount of hip extension (and even less knee extension, proportionally speaking) and it amounts to several drawbacks that don't put it on par with other big movements from a mass building perspective.
Lastly, the deadlift seems to take more than it gives back. Heavy deadlifts have a penchant for wrecking systemic recovery while not adding a whole lot in terms of muscle building. Does this mean you should exclude the deadlift from your mass-building arsenal? Not at all. In fact, I usually include deadlifting as a part of mass building programs because it's a tremendous tool for building overall strength.
A Better Option for Size
If you want a deadlift variation that offers more bang for its buck in terms of building pure posterior chain mass, this is a superior option:
Stiff-Legged Deficit Deadlift
You can place a big emphasis on both the stretch portion and eccentric portion of the movement, and that means big-time posterior chain growth.