Sorry, no... The baseline should be a character with a starting 16-18 in the primary attribute with a "Magic +X" weapon or implement with no additional conditions.
This baseline would be too far off reality. The game system protects you only so far. Yes, it's possible to have a level 30 character who swings a 2d6+13 shortsword. But looking at either the hit points of a standard level 30 creature (around 270), or the kind of damage your typical level 30 character can dish out, this is not a reasonable baseline. Monster hit points increase at a certain rate. Therefore, character damage has to increase at a proportional rate. Magic weapons and natural stat boost progression is simply insufficient by themselves.
It is the assumption that characters will have 20 starting attributes and munchkiny items like the Iron Armbands or Staff of Ruin what breaks the game and forces DMs into making Level +4 encounters the "norm"
It's a matter of preference I suppose. You say munchkin, I say baseline. Out of the gate, the game had problems with monsters having high defenses and high hit points. In time, these issues have been resolved with feats like expertise, lowering elite/solo defenses, lowering solo hit points, and increasing damage with item bonuses. With these tweaks combat was taking a more desirable amount of time, but this time, monsters weren't dishing out enough damage. So monster damage has been tweaked. These tweaks have brought us to a pretty good equilibrium. Going back to no
item munchkin bonuses to damage would just be a step back which would again require adjustments to the system.
My players like to optimize and I encourage it as DM. Level+4 encounters are certainly not the norm in my games. As a matter of fact I don't believe I've ever used one, except possibly in a case where they made a poor choice and fought two encounters at once. I find that level or level+1 encounters are sufficiently entertaining, and level+2 or level+3 encounters are sufficiently challenging. I've used level-1 encounters in cases where there is a time pressure, and wiping the encounter fast or forgoing a short rest can have advantages.
In the long run it really doesn't matter which knobs and dials are being turned to create a fun, fast and furious combat environment. Add bonuses to attack and damage, or shave off defenses and hit points from monsters. It all has the same goal.