Speaking from experience, at shipping time of a new site performance testing is done, and the developers are asked to improve performance until it is just good

Speaking from experience, at shipping time of a new site performance testing is done, and the developers are asked to improve performance until it is just good enough. So it doesn’t matter how big or small the site is, unless by shipping time it is already faster than desired it will only get optimized to run as fast as every other site, but no faster.