It’s not just mid game… Anything past Act 2 normal is a slow grind.
You could stumble across The Gnasher, Deathspade, Bladebone, or Skill Splitter in your normal playthrough but you can literally buy a War Axe off a vendor and do more damage.
There are no viable runewords for early levels. The ease of access to useful gear is a big factor in progression.
Weapon bases having such disparities in damage does nothing to alleviate the issue. Weapons already have affixes associated with increasing damage. Having bases with such large disparities only compounds the problem.
When virtually all normal unique/set weapons become worthless past Act 3… 