Well actually he didn't really do any of the techy stuff if I remember correctly he asked his friend to basically do everything for him, he hacks the stark computer bios in the suit for him and unlocks it, he rewires the webshooters stuff for him, holland never did any of that stuff.

Also you're saying home made tech before he met stark? He didn't have any webshooters before meeting stark all he had was a rough suit that was basically just a mask.

Maguire's spider man doesn't actually create anything either, none of them do. its not as if spiderman is an inventor. But when he goes to college he actually takes high level science courses and eventually meets the famous doctor oc, later doctor octopus, he talks with his teachers as well as doctor oc in depth about science theories and applying them to experiments. I remember his knowledge of science helping him too when hes fighting in certain conditions.

I mean at the end of it all, none of the spidermen created anything really verifiable that we can go "see this spider man made something techy and none of the other ones did."

Basically they all possess higher than average intelligence, but at the end of the day they don't really ever use it to create anything.