As someone who used to work for a web optimization company, yes mountains of Javascript. Javascript for analytics, javascript for transitions, javascript for DRM, javascript for updating pricing in real time, javascript for fonts, javascript for colors, javascript to lazy load the images....six different style sheets and images that are downloaded and resized client side...and this is just the navigation bar.

Just for fun I like to pull up the browser diagnostics on pages, and watch the absurd number of requests build up. It's insane how much junk is downloaded on seemingly simple sites.