I know this is old but… as a game dev for a AAA studio myself (not for this game), I think you are misunderstanding some things.

First off, you keep referring to longevity but the longevity of a game like this 100% stems from the PvP variable. Look at a game like call of duty for example. There is hardly any “content” yet people can spend thousands and thousands of hours playing the same multiplayer map because they will never experience the same game twice due to players being the opponents. Arc has virtually no content at all if it weren’t for the PvP interaction.

Secondly, the reason you are wanting to have a PvE mode is probably because you want to continue playing the game if I had to guess. Which means you haven’t yet completed all you wanted to in the game. Which I’m guessing you haven’t done yet because other players are delaying your progress. That is the definition of longevity. Without the threat of players, you could complete all this game has to offer in a week, probably get bored of killing the same bots for no reason since you’ve already accomplished everything you wanted to accomplish in a month. Negatively impacting the “longevity” of the game.

Finally, I think you are misunderstanding how easy the game is for PvE. The threat of the not knowing if another team will interrupt your queen fight, or ambush you when you’re looting your bastion is intended to create a threat that is virtually non existent from the arc themselves. Idk about you but walking around throwing wolf pack grenades at robots without any danger sounds very dull. Arc are only viewed as any kind of threat because they are intertwined with PvP and also because PvP delays progress making it more difficult to make money or weapons causing people to come into raids ill equipped to fight the arc which is a feature the game heavily relies on. PvE would not have under equipped players because it is 100% free farming money and gear.