My MIL was in her 70's when her intolerance to gluten popped up. Doesn't fit allergen criteria and refuses to be Celiac tested because doctors just want her money
(FWIW - I love my MIL dearly, she lives with us but she and I have very differing opinions of medical care).
Regardless of what the diagnosis is - she cannot eat gluten (and a few other things as well). And she misses it dearly. And has struggled with finding a gluten free option that tastes gluteny (if that makes sense).
DS1 on the other hand has only had items containing wheat and barley a few times and it has ended badly even with just trace amounts. He is much more tolerant of gluten free/egg free items than she is because honestly, he has never had any different. He doesn't look at a menu and say "Oh look at all that delicious food that I cannot eat" - he is more of the "Oh goody, I can order a bunless burger". Not to say he doesn't have moments like you do. He failed an egg challenge a few years ago and he really liked the taste of eggs. In his head, eggs limit his choices way more than gluten does (and I do agree that egg free and gluten free shopping/eating is harder).
My banana and eggplant allergy are late in life developments. Yes, I miss both of them. And I still remember the taste of baby aspirin (because I am older than dirt and aspirin was still recommended for kids). At the same time though, I am usually not limited to options short of going to a middle Eastern restaurant so my experience is different than yours.
Irony? My MIL moved in when DS1 was 9mo old. She used to lament over and over and over again about how she wanted to be the Granny that baked for him. I admit, when he was younger it was much tougher because his list of false positives was huge. But she never wanted to make the effort when he was down to just gluten and egg. My SIL went out of her way though and she was avoiding none of it. Now that my MIL cannot tolerate gluten, she has been the one to take up the baking end of things. (Caveat here - I was not great at baking that stuff either and he was happy with Enjoy Life cookies, EnerG bread and many other prepackaged treats but I don't think felt this need to say over and over in front of him that I couldn't bake for him).