Hindsight is 20/20 and the „Internet“ was a mainly US centered university research project that was thought of as a toy by the far majority.
Everybody thought they‘d have a replacement for the initial assignment once things got serious... for more fun, google ipv6 history ^^
And that in the interests of working within the physical hardware limitations of the day, very smart engineers made the best choices they could?
Jesus.
Because of such wasteful allocation we got this "wonderful" thing called NAT which basically killed most of innovation in area of networking and IPv6 which is taking over 20 years to adapt, because most ISPs hold to IPv4 as long as they can because making this switch requires some work.
Or, if my networking trainer at a Cisco course is to be believed, the geniuses that made IPv6 subnets contains 65k hosts at a minimum, when due to ARP requests all traffic would be dead at that scale.