I actually like this system. It reduces radio congestion and you don’t have to worry about that late landing clearance being stepped on.
But there is a gotcha which may or may not be a factor in this case.. If you do miss the frequency change to TWR (which comes at quite a busy phase of configuration change etc) there is no memory trigger at the point you would normally (in other countries) expect a clearance. You are thinking ahead, not back where the error occurred
Yes I know there are other cues which should clue you in but the brain is a funny thing when it gets focussed on a task.
Anyway it's not an excuse, just trying to give an insight into how a minor difference from your normal habit pattern can erode your passive defences.