Many of the posters here didn't deserve to pass test and get the license.
HTA is clear here: when you merge to a line you have to yield to the incoming traffic. Period!
People that don't change the line (in this case left line to you) have right of the way. Period. Same as when you are overtaking.
You are allowed to merge when it is safe to merge - meaning when there is gap and when your speed is matched with the traffic.
There is no early or late merging issue - you are merging when it is safe. When you are at the end of the merging line and no gaps in the traffic, what then? You have to stop, unless you are willing to break another traffic law.
Why the merging is never the problem in EU countries, but only here?!
Please be advised that we are specifically discussing merging in congested rush hour traffic. If you re-read the previous comments, we are mostly in accordance that in free-flowing traffic, you merge when it is safe to do so, as per the HTA.