I play hardmode everyday, there's like 1-3 drops all day for a rare, if even that. Also the 10% for bosses only isn't even that much, here's an example: Normal bandos tassets all boosts no active well (1/73), Hardmode bandos tassets all boosts no active well (1/67). I don't know why anyone's overreacting about 10% boost towards bosses, when it comes to actual numbers. The non bossing pvm side is much harder also, whip on normal (1/79) whip on hardmode (1/199), Dwh normal (1/793) dwh hardmode (1/1999), and so on.
Edit: Not to mention, mboxes in normal mode, blood money shop differences, normal mode drop rates before nerfs/chaos ele nerfs/dupes that happened in normal mode eco that never touched Hardmode eco.