I would argue that the UX was designed by engineers with a solid sense of what they wanted and what the customer would want. Whether Larry and Sergey were aware of it or not, they were acting as a designer. I've seen many engineers with exceedingly poor design sense.

For instance, a valid choice for Google would have been to clutter the landing page with advanced search options or ancillary material as so many of its contemporaries did. In this case, I would argue that the engineer was skilled at a small set of design tasks.

For what it's worth, I'm an engineer, but I'm close friends with designers.