No. Ultra-processed foods predate these increased cancer rates by decades, it started after World War Two. Pollution was far worse in the past, coal was nasty. Meaningful healthcare implies modern healthcare, it detects cancers it doesn't prevent them.
It's almost certainly plastics and other chemicals that we are exposed to on a routine basis. Prior to the 90's most things were still glass, metal and wood. Now even our clothes are plastic and everything is stored in some chemical blended storage.
I'm not discounting the role plastic has played, I grew up when Teflon was used on everything, even the living room couch. Plastic was the miricle do all material and it was cheap. And it was perfect for the "disposable" generation who liked to throw everything away instead of dealing with it (looking at you Mom and Dad).
Living in a large city that has tripled in population since my youth and I can promise you pollution has gotten worse in the last couple decades. Unless you're lucky enough to live in a rural area, pollution is taking its toll on your body as well.
It's all bad for you when you get down to it. I sincerely hope humanity can find its way off plastic in my lifetime.