Ok, I guess I have no idea how elemental damage is calculated. I get with status ailments you have to hit them a bunch and then it builds up causes the ailment so hammer sucks for that, but didn't think elemental damage was like that.
Looks like I should prioritize other skills and higher DEF armor then with my hammer build.
Elemental generally adds a flat damage number per hit (some attacks have elemental modifiers, but flat damage is a general rule).
So let's just imagine that a high element bonus adds 10 elemental damage per hit.
For hammer or GS it's not much, since your regular attacks are hitting for 100+ raw damage. Doing an extra 10 damage on a 300 damage "golf swing" attack isn't a big deal.
For dual blades it's huge since you are doing loss of little attacks at about 30 raw damage, so adding 10 more is a big deal.
The elemental damage in the weapon stats is usually higher on hammers than dual blades, but not enough to offset the "hit rate".
I think elemental weapons and damage got some buffs in iceborne. I heard that GS got some big elemental damage modifiers added to some charged attacks but I don't know about hammer. However, raw damage is still best once you factor in the critical hit modifiers in most builds. Criticals don't affect elemental damage unless you use special "critical element" armour set bonuses.
