Even for a session? The OP doesn't give a time frame.
You can play the game fine without endlessly murdering things. It even says so in the DMG!
. . . but I know, nobody reads the DMG.
Obviously it will be rare for all 3 pillars to be engaged in a single moment, so most of the time only 1 or 2 will be going on at any given time.
You're just twisting things around now.
No one has said that combat must be occurring at all times.