Same in Germany (~1€/l for milk, 2€/l for pretty much all milk replacements.

You can obviously buy more expensive milk to, which would give it price parity... But there are also more expensive replacement products. On average, the replacement products cost about 50-100% more.

The only way to save money via vegetarian meals is by making everything yourself and not the finished products from the supermarkets (at that point the relationship reverses - making meat meals about twice as expensive)

And I feel the urge to point out the obvious: the reason why the vegetarian replacement products get ever more space in supermarkets is precisely because they've got a gigantic profit margin, whereas the "traditional" milk/meat products have razor thin margins