I think a combination of factors ontributes to this.
One is the prevalence of convenience food. There is no respect for proper food, it has to quick and cheap.
When I grew up, on the continent, my mum always cooked proper food, home made biscuits, and my dad cooked twice a week. They even made their own bread. Nothing was " forbidden" as lng as it was quality food. So no cheap and nasty chocolate, no fizzy drinks ( but 1 glass of juice a day was fine), crisps only at birthday parties. And lvely homemade cakes.
To offer the family good quality food requires dedication and time, whoch most couples do not have as both work.
I am grateful to have been raised with an appreciation for food, and therefore craving those same proper foods I had in my youth ( minestrone soup, home made lasagna, beef stroganoff, lots of wonderful salads, the big treat that is panfried piece of fish and fresh spinach). I am almost imune to junk food as a result, it does not hit my pleasure buttons.
This is not just some personal remeniscing. food companies know that people crave what they ate in their youth, and target kids.
Interestingly, McDonalds barely makes a profit on their happy meals, however, it teaches kids that mcD is a treat, and they will crave it when older! It is their long term strategy. It seems to work. I am not making this up.
It is like the, for foreigners, incomprehensible passion Brits have for Cadbury's, a very mediocre poor quality chocolate, that they like as that is what chocolate was like when they were kids.
Partly, we are being played by large corporations who have done thorough psycological research!