There’s actually less specialized parts these days, that’s what put Lego in trouble in the 90s, I think what GP commenter was referring to is a ton of the studs and cylinders and 1x1 diagonal parts that Lego includes, that are “fluff”. These parts are extremely cheap to produce, so you may have data that looks like price per part is flat, but in reality that’s because more of your sets are now from cheaper detailing parts.