There is no way that's true. No matter how far a person wandered they're not going to come across a bell pepper, lettuce, carrots, potatoes and any meat they could want.
You're perspective is skewed. Your knowledge only includes the local plants that we have created into our international rummaging choices. Bell Peppers are just one modern variety out from the ~30 species of chilies we've discovered. Same for carrots and potatoes and lettuce. I look at the variety of edible vegetation I can get at the grocery store and the only thing I really think of is it's a good day that I don't have to walk 20 miles to the fruit trees to pick the fruit before all the animals do.
Meat? tons of variety, there are like twenty different cat to dog sized animal species in my Montana wilderness before I even have to get to the large herbivores that have less variety. And meat is special anyways, the mink or weasel you can kill is chock-full of 2-5 years worth of collecting resources from various animal and vegetable sources.
Pine needles "contain more Vitamin C than an orange" (I didn't see it specified if that's by gross weight or dry mass) and make decent tea, and many cultures still boil and eat or cook with pine cones.
Modern crops are amazing, but we are literally surrounded by new and forgotten sustenance. It's not always pretty, tasty, or toothsome, but it's there if you have the time and will to turn it into food.
I'm also reminded of villages that "modernized" by trading their old fashioned cast iron cookware in for aluminum and began to suffer from anemia as a result. Iron is abundant in the crust, and eating mineral-rich clay is still practiced by humans and animals around the planet, but their solution was to put cast iron charms in the new pots for luck. It's possible they were in iron-poor areas, but if they were swayed to abandon their traditions by the appeal of commercial marketing, it seems likely they mught also eschew any dirt-eating practices they once might have had.
Meat? tons of variety, there are like twenty different cat to dog sized animal species in my Montana wilderness before I even have to get to the large herbivores that have less variety. And meat is special anyways, the mink or weasel you can kill is chock-full of 2-5 years worth of collecting resources from various animal and vegetable sources.