The biggest issue is that as long as you are not dangerously out of control, in other words avoid a slide or lock up, you can brake as late as you absolutely want to regardless if you are going to make the corner and just go wide. The rule needs changing that you have to be able to make the corner inside the lines otherwise this legal pushing off the track will just continue and make overtaking on a corner between two similar performing cars almost impossible.
Turn 1 was not a pen man. See the race starts in COTA for every year and there will be atleast one car being pushed wide in turn 1. Hell in 2015 and 2021, the driver in P2 pushed out the pole sitter at T1. In 2017 and 2018, Hamilton conceded the corner and didn't try to go side by side which is why he was not forced wide. The nature of the track coupled with cars being on cold tyres always leads to that.