When looking through the crafting section it says you can keep picking an item up the the maximum time listed, and most things have a maximum on them. I noticed Schematic doesn't list a maximum, so if you continue to use you Triumphs or extra advantages can you continue to reduce down the difficulty on each of the templates. Eventually getting them down to a Simple (-) roll if you continue to choose schematic for the Template.

RaW, Yes, you can keep choosing the schematic option down to, theoretically, simple difficulty. At the table that's dangerously foolish to let your players do though. I require an additional triumph per each schematic chosen. I.E 2 triumph the second time, 3 triumph the third time, etc, etc. This makes it possible, but not likely, that a player will get too good of a schematic. Rules as Written it's too easy to simply spam creds and time to get down to simple difficulty and spam incredible gear.

Sounds a bit harsh if I'm honest. getting to a place where you can get those kinds of rolls costs dearly in the xp department. But yeah. for /most/ things you can remove those pesky purple dice multiple times per roll if you have enough advantage and triumphs. The two exception I know of out of hand are armor (states may only be taken once) and utility items (**** it) that don't have the schematic option at all. Note that while you can't buy multiple schematic options on one roll for armor you can take it over the course of multiple rolls to still get to 0 diff.

This is correct they say the balancing factor is time, for the more difficult things, for example if it says 48 hrs, getting those 48 hrs outside of game time, certainly in my campaigns would perhaps take half a campaign of time working on the project. Also money should also be a factor. So dropping the easier items to a simple check would be easy enough, but dropping anything that starts with 4 purple dice to a simple check is going to take a good length campaign to manage.

Another thing to add is that difficulty dice are very good at adding threat. In fact, they're better at adding threat than either ability or proficiency dice are at adding advantage. If you're making something that has a baseline difficulty of Hard or Daunting, you need that schematic reduction along with talents and high skills just to have a decent chance of getting benefits out of crafting instead of gear with drawbacks.

As people say, time is a factor too, especially when you have party members who are eager to have you supply them with weapons and armor. In my droid technician's campaign so far, the only thing I've had the time to iteratively craft is simple tools because of the low 2 hour crafting time. The next downtime is probably going to be devoted to crafting our Politico an energy pistol, and then the Gadgeteer wants new armor, and by then the Scoundrel will probably be looking for a new gun or two. After that, maybe I'll have some time to build some stuff for myself or fish for schematics. I'm not going to be getting a Hard or Daunting template down to Simple anytime soon unless the GM decides to drop a month of downtime and a dumpster full of materials on us.