Very good story. I'm not sure they can technically call the children who fought Voldemort veterans, but they certainly deserve all the help they need to live well after being left to deal with their elders' failures. I can understand the reason for the crime and I'm glad Harry's working on a solution.
Hermione will certainly dive into her new cause, especially once she's used the computer to do research a few times. She and Severus will be a force to be reckoned with.

Another natural reason for leaving the magical world. For couple of Ravenclaws, the chance to keep learning is probably incentive in itself. They gave their son a choice and he made it. Harry's concerned about regrets, but every decision offers that possibility. I wonder how many kids regret going to Hogwarts? If they grew up as muggles and want to go back, catching up with their education after seven years would be difficult, maybe too difficult for many, so they just muddle through as wizard or witch.
Now Ron is thinking about what he's been told and he's beginning to see that there are benefits to the world Hermione was born in. Enough benefits to worry him.

Ron isn't aware of himself being biased but of course he is. The people who left the magical world seem perfectly satisfied. I guess I understand why he feels a child kept from their magic would be deprived. He's never been without magic.

This concept is both unusual and highly believable. The wizarding world is so enclosed and backward on many levels, so I can imagine thinking of magic as unnecessary if I found the muggle world had more to offer. Severus Severus seems perfectly happy with the adjustments he's had to make to live there.
Border crossing crimes also makes so much sense. I imagined it more the other way around, with wizards having the perfect means to sabotage modern security and escape without a trace, but your development of Rejectionists and their unusual needs creates a perfect scenario for this plot.
Snape the dad is so mundanely wonderful that just reading about him bouncing his daughter or scolding his son is charming. Then he proves to still have his bite when the visiting Gryffindors nearly wreck the power running through his fridge.

What a fabulous short story! Definitely left me wanting more.

Excellent story, well written and thoughtful. The actual finding of the culprit was secondary to the thought process associated between the two cultures.i thoroughly enjoyed this story.

I love the slow build. You do such a good job with this. And several lines had me chuckling too

very nice fic. I especially liked the word "anti-tech" for "magical"... well done!

So if it's not one of the Rejectionists then who is it and why? I am curious if it has something to do with the Rejectionists at all but at the same time I'm sad to see this story end.

Excellent chapter with a very sympathetic character. I also really liked room and Harry interplay here. I'm very interested to see how you wrap this up in just a few more chapters. Honestly, I thought you were going to have George selling the potion, but I guess see mungo's makes more sense

I'm enjoying your packing of the street and how you tie on their real lives

Room is pretty obtuse here, but I think that's the point. You make a good point for the rejections here

Hi love Snape here, the contrast of his gentle care for his baby and his s surly time

Excellent scene of goblin culture, I enjoyed that a lot!

Again a solid reason to leave the wizarding world. And if more people still don't trust Snape's brewings and get their potion for a much higher price, that would be a sound explanation for the thefts.
As for other reasons to live as a muggle, I think our technology has changed so much between the time Harry started Hogwarts and today that magic might be not so enchanting anymore for muggle first years. Or to put it the other way around: staying in a world without this technology might be not so appealing anymore than it was before. I think the wizarding world would look now even more archaic when coming from a muggle background than it did for Harry and not just from a technological pov but also in sociological matters like race, class and gender equality, where all kinds of developments have been supported and sped up by technology.