Open any document. Single click somewhere within that document. What do you expect to happen? Do you expect your cursor to be placed where you clicked, or do you expect the entire line to be highlighted? My guess is that you expect consistency in every application doing the same thing for a single click.
Just because one browser decided to change how they react, and everybody else copied that behavior, does not mean it is the correct or expected behavior. You've just gotten used to the difference that was forced on you, but imagine if every application on your desktop reacted differently depending on how many times you clicked a spot? What happens when they also start modifying the results of a right-click into something unexpected like clearing your cookies? Is that also OK just because one browser started doing it and every other browser copied that function?
On my system if I single-click it highlights the entire address. If I double-click it highlight the word (usually the parts between period and slashes). Triple-click highlights the entire URL once more. However I was not aware of the click-and-hold option! Thank you for that, it will certainly be helpful in many instances!
I still have the problem of grabbing something like an Amazon address, where I don't want all their nonsense when I send it to someone, I just want the short link to the product. Unfortunately if the description in included in the URL (as it is in most Amazon listings) then the end of the direct URL is outside the right side of my address bar so I used to be able to just click towards the end of the visible URL then cursor over to the end of what I want to grab. The new behavior means that I either click, then have to wait a couple seconds before clicking again to place the cursor, or I click once then have move the cursor all the way from the end of the URL to get where I wanted. I think your method will let me highlight a small portion at the end of what I can see and then move the cursor from there, so I'll wait and see how that works out in practice.