That is a factual statement.
But look at the teams they have had to beat to do that. That was why the Germany win was so big - it was the first decent country Southgate has actually beaten in tournament football. Although a pretty poor vintage for Germany.
In the past tournaments we have gone out to Brazil, Portugal, Italy, a good German team. Southgate has never come up against a team like that (apart from Croatia at the 2018 WC) and he lost. You can only beat what is put in front of you but I do think he's been lucky with the draws he's had.