I feel the same -- actually in classic gamer conspiracy theory fashion for a while I was starting to think it was hardcoded to give you a few blessed drops in the early game and none later, because on both my playthroughs that's what happened. I think the reason is that earlier enemies drop items more frequently in general (lots of junk like cloth) so the odds of seeing blessed things is higher.
Not helpful for vanilla, but in my mod (Arcanism) I've implemented some mechanics to help with this that might interest you:
- base bless drop increased to 1.5%
- new line of consumable magic items called Scrolls of Luck of Soluna that are reasonably expensive and come in 5 tiers. They all triple bless chance for dropped items for 15 minutes, but only for enemies up to X level -- the idea being that they're something you can use at any point in the game, but the cost is scaled to ensure it remains a gold sink based on where you're up to. They also function as an extra "try to play without dying" mechanic since they're so expensive and you lose the buff on death.
(NB the version featuring these among many other huges changes is still in testing but it's working pretty decently, just haven't felt rushed to release the update as I don't know if anyone is actively playing Arcanism atm other than me)