The wacky approach to column types came from SQLite's origins of being closely integrated with Tcl. Knowing that doesn't somehow mean it was a good default worth carrying on for decades.
The reason it remains unaltered by default is because one of the goals (and accomplishments) of SQLite is that the on-disk-data-file is completely backwards compatible, and cross-platform. This is a very important feature in some situations, and not lightly tossed aside because some old default or system is not in vogue anymore.
The latter is the luxury of end-user software unburdened by decades of legacy compatibility obligations.
CREATE TABLE mytable (
id INTEGER PRIMARY KEY,
created DATETIME,
mything JSON
) STRICT;