I just built my first Imperial Fists list and it only cost me like $400 for a very competitive army. Very good Space Marine armies are really easy to build right now, especially with IF or IH.
The Primaris Dread has nothing on the Leviathan though which has a regular Astartes inside. Guess the guy in the comic is just a newfag. Do you even founding legion?
Fun fact: While the standard Space Marine Dread can preserve the entombed pilot for millennia, the Primaris model is deadly to the pilot and will kill them within a century.
Again, after ten millenia, Cawl made some improvement on the STC and Emperah's designs (which in itself is impressive). So more stuff = bigger = better (in 40k at least).