Why are Archguns so... incredibly useless?

Maybe this is because I'm a newish player, only MR 14 and with just Steel Path unlocked, but... why do archguns feel so powerless compared to other guns? ESPECIALLY considered the effort to get them! I love heavy weaponry, in all games, so I really wanted to give one a go in Warframe. But unfortunately, the only guns that really fit the bill in Warframe are the Archguns. Know what all you have to do as a new player to get a Kuva Grattler working for you as a reliable primary?

  1. Run a dozen Kuva Liches hoping it drops.
  2. (Optional) It finally drops. Get a 22% damage roll. Cry.
  3. Max out Solaris rep so you can kill a profit-taker for the Archgun Summon tool.
  4. Level up Little Duck rep to Rank 3 so you can afford a Gravimag for your archgun.
  5. Grind dozens and dozens of Corpus missions of varying levels for Crowns.
  6. Actually find people willing to run Granum Voids in this day and age so you can grind out Protea Original for the Dispensary subsume (seriously why is she not in the Circuit rotation??).
  7. Spend another dozen hours grinding in on of the few high-level archwing missions in the game, because archgun mods don't drop through the normal course of gameplay like regular mods do.
  8. Sink 5 forma into it to reach level 40.
  9. Finally, after about 30 hours, you have it up and running. Cry again as you realize you could have had a far better gun from running Duviri for a few hours and getting an incarnon primary.

Seriously! Archguns don't get arcanes or exilus mods, the mods they DO get are incredibly limited, and a single random riven costs 35 arbitration essence! Not to even mention the fact that there are missions where you flat-out can't bring them.

They desperately need buffs - there is genuinely no reason for the casual player to use them over their other weapons, and even if you focus your entire build around making them work, a normal primary will always be miles better in terms of both usability and damage.

That's... really disappointing for a weapon type that's supposedly meant to be these really huge, really special, amazingly strong guns - overkill made manifest. Thoughts?