It's hard to say that "things are more expensive" than they were a few years ago without looking item-by-item to see if the cost of those items are really higher. It does seem to be the same sort of thing on both sides of the pond: higher costs seem to be down to what you're spending your money on. And, yes, people do pay for convenience. I wish I could keep up with the food needs for my kids, but they're teenagers, meaning they eat a lot (especially my boy, who always seems to be hungry).
For those of us old enough to remember, frozen food (which were once called "TV dinners") used to be really awful. Now, you can get good quality food in the freezer. It isn't - and never will be - as good as freshly-made food, but it's certainly better than it used to be. I frequently have to supplement a big batch of stew with frozen pizza. And, as much as I feel like I'm failing my children when I do this, I completely understand why the industry has flourished.