Your mother probably tried as much as she could. Don't discount what she probably did.
Your kids are different than you. They might allow a lot more than what you might have allowed.
I'm the oldest of 5. I was the "good eater". I once ate the potatoes from my brother's plate b/c we weren't allowed to get up from the table until HE was done, and I was tired of being there (we'd probably been there an hour or so).
My full brother, 2 half brothers, and half sister were ALL picky. I was not.
I'm the one with the food and environmental allergies. NONE of the other 4 have even a hint of those things (though my full brother doesn't much like citrus fruits so he doesn't eat them or enjoy them in his home (if you open an orange downstairs in his HUGE house, he can smell it upstairs in his closed bedroom, that's how sensitive his nose is)). No environmental allergies, no tendency towards asthma as I have, no food allergies at all.
I wish I'd been more like them! I wish I'd protected myself and had NOT eaten the things that were vile to me, instead of trying to be easygoing and nice to the family.
My mom tried really hard to get my brother to eat, tried in kind ways (my dad tried to get him and his two other sons in MEAN ways...neither worked!)...but when you come up against a stubborn mule like my brothers are/were...nothing short of knocking them out and forcing it down was going to make that food get eaten.
My mom also had the memory of being forced to eat everything on her plate as a child. Most meats made her nauseated, but she had to eat them. Most nights after finishing she left the table in a run, trying to make it to the bathroom to throw up the meat she'd eaten. So in the recesses of her mind, she knew that eating food that your body is saying NO to isn't the best idea ever.
DH and I go back and forth on the levels of coercion we do with our son, but it turns out that force doesn't work at all with him. What does work is being nice and easy, just offering, never forcing, and after many many tries he will often have something. He officially hates garlic, but eats hummus and now is in love with pesto, and he KNOWS that those things have garlic in them (I don't sneak ingredients into foods, because I respect his body too much to do that) but likes them anyway. He also says he hates ginger, but will eat foods that he knows have ginger in them (and not just powdered ginger in gingerbread, but fresh ginger that he watches me grate up and put into foods). Funny boy.
My brother used to refuse to eat anything but mac and cheese, totally plain hamburgers with only ketchup, and peanut butter and honey sandwiches (my mom got our lunches switched once, and while I ate his PB&H, he didn't even touch my PB&J)...and now he eats most everything (except for citrus). It's just not worth stressing over, IMO...