Removing the children in Umbraco 13 was more of a technical choice than a design choice. The reason why the children were removed in U13 when you enabled a list view, is because the tree would get too long and performance would suffer. It was not a design choice, but simply a performance choice. In Umbraco 14+, the trees load only an x number of items at the time and display a ‘load more button’ for paged loading. So the performance reason is now out of the way and that’s why the children are now shown.
Currently there is - as far as I know - no way to hide the childeren.