Actually the show demonstrates it really isn't that simple.
This isnt the show
Because portable hextech was rare
(Cait rifle,the hex hammer,jinx guns,viktor laser and claw)
This means the amount the production and maintainance is artesanal and limited to what was avaible to jayce and viktors lab
And stable hexgems were recent development
This means artesanal and easily hideable production and maintainance is no longer here,and then jayce,jinx and viktor go awol (along the hextech notes)
Noxus was trying the equivalent of making a functional warplane from left over notes and bits here and there
This isnt the case here:
We made magic regulators a thing and we are aiming to make them (if we havent already in some capacity) widespread
3 infrastructure projects,hexcores developed years ahead and magic regulators as the pillar for mage law reforms
It means factories making hextech devices,as well hextech crystals,engineers trained on the making,modfying and usage of them as well their inner workings
Jayce,jinx and viktor are at the bleeding edge lf hextech sure
But hextech is no longer super secret tech that barely left the lab
There is likely a small horde of engineers that could build you a zapper if you gave them a few months
You can have hextech making a change or you can have no hextech weapons
You cant have both
