Why do web browsers keep showing the old page when they load a new page

I was wondering why web browsers keep showing old content once a user has clicked a link. It's confusing if one doesn't look at the loader(which is generally at one corner and thus can easily be skipped).

Wouldn't it be better to show a blank white page with a loader in the center till the next page html is received? The current approach has very little to no feedback on whether my click was registered, and the browser is processing it or not. I have myself seen a lot of users spam clicking the links 2-3 times before the browser recieves the next html and starts rendering it.