And IIRC, satoshi added that limit without discussing it with Bitcoin community in advance.
Prior to version 0.3 there was no coded limit. Doesn't mean there was no constraint though.
There were other limits. P2P message size was limited to 32 MiB (and still is, by the way), even if you ignore database locks, and other limits like that.
The database lock effectively allowed block with size 750KB or less and it wasn't discovered/noticed until few years later.