I see what you're saying about that implication. I think the effects were indirect; SQL winning meant that Postgres, even though it started out supporting only POSTQUEL, had to evolve to eventually supporting SQL -- though you are correct that the cause-effect was not as direct and as inexorable as might have been implied in the prose.
I personally think eliding details was artistic license to make the prose flow better without bringing in ancillary details, but that's just me.
Stonebraker did eventually change his mind about SQL however -- if you've watched any of his recent talks he's of the opinion that most query languages will eventually and inexorably converge to some variant of SQL. (he was wrong about Mongo inventing a SQL-like query language, but that's what his philosophical commitments look like these days)
I personally think eliding details was artistic license to make the prose flow better without bringing in ancillary details, but that's just me.
Stonebraker did eventually change his mind about SQL however -- if you've watched any of his recent talks he's of the opinion that most query languages will eventually and inexorably converge to some variant of SQL. (he was wrong about Mongo inventing a SQL-like query language, but that's what his philosophical commitments look like these days)