I feel like 3 diamond cards are too rare when considering their quantity

Been playing for a year and the last cards I need for every set are always a handful of 3 diamond cards. Even for deck building, 3 diamonds are usually the ones I'm missing a play set of. 4 diamonds I usually do end up getting them all, but there's not a lot of them so maybe they're just easier to trade or acquire.

I imagine it's the higher quantity of 3 diamond cards mixed with their rarity that makes them feel more rare than anything else.

Anyone else experiencing this?