Same here! I still remember my play kitchen and it was so colourful (red, yellow, blue, green). Also I remember my clothes being colourful both as a baby and as a toddler/child.
As a millennial who has many millennial friends that are now parents it's amazing how much of the previous generation they absorbed (more millennials were raised by boomers than gen x) one of which still aspiring for the goals boomers had mainly home ownership, marriage/kids and overall placing an importance on perception/image. Obviously this is not all millennials but enough that it's safe to say the influencer industry on IG is being sustained by primarily white cis middle class millennials hence the algorithm in showing these "minimalist" neutral aesthetic.
I remember in the late 90's early 00's when many offices were beige and that is primarily the vibes I get with this whole beige sterile, excuse me minimalist trends.