This is well discussed in a brilliant book: Marissa Mayer and the fight to save Yahoo! by Nicholas Carlson.
Google won over Yahoo in Search because Yahoo's majority of income came from their Advertising, which made their homepage cluttered with several ads which might not even be relevant.
Marissa Mayer was the Product Manager for Google Search and the primary focus was UI/UX. Minimalism is key here.
Yahoo! never really knew what it was. Google was very well known to do one thing, the best - Search.
The minimal web design also ensures that you get to see what you will expect to see.
For example, let's say Person A keeps Yahoo! As their homepage and Person B keeps Google as their homepage.
Person A may get all sorts of ads which add up to the data usage and these ads might be inappropriate or unrelated and so, it's an unexpected outcome. Also, loading these ads up might take longer than 3 seconds, which is the time it takes for your user to give up on your service waiting.
Person B knows what to expect from their homepage. It doesn't have any ads, a whole lot of white space, a Google logo in the middle, and interesting doodles signifying of different events worldwide once in a while.
Animations, Transitions, Buttons, Filters, etc. consume time and lead to more data usage. Definitely not something you want to add up into the loading time of your website when it's the most visited webpage in the world.