Jake I think this woe certainly has the potential to very easily be more costly, but I say that as someone who was always feeding the family very cheaply before and carbs were a huuuge part of our diet. We also got them very cheap, bought spuds by the 25kg sack for example. Replacing those with swede/celeriac/turnips is a lot more expensive, but much much tastier and nice to have the variety.
Similarly we bought basmati rice for £1/kilo in massive 10kg sacks, and cauliflower or whatever is naturally more expensive as it is fresh.
To be fair, I don't think my eggy breakfasts cost any more than porridge with milk, cream, raisins and syrup did.
And again in the past we ate loads of onions, carrots, peas and tin toms are they are really cheap veg. Broccoli, fennel etc is more costly. However, stuff like mushrooms, cabbage, radishes (I now have these instead of cherry toms/carrots in salad, lovely crunch too), frozen spinach etc is actually pretty cheap per helping.
However I think it depends where you are starting from and I think as we get used to the woe we will find ways to make it more economical (at the moment I am excitedly trying loads of new recipes and that is always more expensive).
For eg, there are a number of soups on the recipe thread based on broccoli/cauliflower or spinach, and actually I;m sure the frozen veg would be perfectly fine for this, or in a curry.
And whilst say cream/cream cheese is more pricy than butter per litre I certainly do not replace like for like. Say in the past I made cauliflower cheese, I might make 1 pint cheese sauce. Now I would make a sauce of cream/cream cheese and it would be more like 1/4 pint, partly because it's a thinner sauce and goes farther, partly because it's so much more satisfying you don't need as much.
Meat wise, mince is really good value and you can do pork/beef/turkey and make all sorts with it.
Bacon and chorizo pack a lot of flavour.
Frozen fish is very cheap. Tinned can be good value.
Value prawns aren't too pricey.
But undeniably, we are eating more meat and fish than we used to. Used to have a lot of pasta & pesto type meals with a sprinkling of bacon. So yes, in summary, I am finding this more expensive (but tastier!) but suspect there are ways to reduce the difference.
Think what you will save on biscuits, cakes, fizzy drinks, fruit juices, crisps, booze!, sugar, flour, pasta, rice, spuds etc and remember that that money is there to be now be spent on much better food.