You are making some tremendous claims. Do you work for Tesla or are you speculating?
Since you "asked":
I had an Opportunity to attend the Gigafactory Opening Party Last July 2016.
And toured it, at least the parts that were open to the Tour groups.
Our group toured Building "A" had some robots and Assembly going on in Level 1 (it is three Levels high.)
Buildings "B" and "C" were being built out as part of the Panasonic Battery manufacturing plant. Lots of work was still being done, some two and three story racks were being build for battery storage. A couple of the self-guided Robots were running around (in operation). Saw a couple of the first 2170 batteries.
We were dropped off from the bus deep inside Building "D", right at the door to Building "C". Two outer side walls were up, base for the roof was on. No slab or any of the floor were installed. There was a huge open area (no wall) to attach to future Building "E".
Since then, Buildings "E", "F", "G" and "H" have been fully erected.
Walls are on.
Roofs are on.
The numbers of cars and trucks in parking lots has quadrupled: some Workers are still Building the Buildings and further developing the site.
Some Workers are Panasonic employees, manufacturing Batteries.
Some are Tesla employees
No: I do not work for Tesla.
But, I do have almost 40 years professional experience in Design and Construction: this is a HUGE project.
And I have worked as part of several teams building very large projects, have spent a lot of time both in the office working on the drawings AND in the field at the project site working in the Job Site trailers.
I view the Gigafactory as a series of large Horizontal Buildings, and because of the operations and manufacturing process, many of the functions can be independent functions from other buildings.
I have toured the Fremont Factory three times.
It is bursting at the seams.
And they are landlocked. They can warehouse lots of materials around Fremont, but between new parking structures for full employee parking lots, they are space constrained.
I have toured SpaceX.
It is landlocked, except for the Boring Company initial test site. My friend took me to top of their four story parking garage.
Everything is scheduled as "nick of time" for manufacturing and delivery."
Elon and JB spoke about "Buildings Building Buildings", where raw materials are brought to one end of the building, and the finished product comes out of the other end of the building.
Not just battery packs or drive units: fully finished cars.
It takes a small army of design professionals to get each of these buildings DESIGNED.
Then it takes and even larger army of skilled and dedicated Construction Firms to manufacture and erect and assemble all the pieces, pull all the miles of wire and cable, etc.
And LOTS of Money to pay for land, material and Labor.
LOTS.
2 + 2 + 2 is kinda easy to figure out.
Tesla has announced Model Y as a future project. I really doubt Fremont can fit all the stamping and storage for the parts and additional employees and the parking for the Model Y @ Fremont.
Maybe, but probably not.
Probably see it in Sparks.
Tesla has also announced and presented the Semi, which they are taking orders for.
Sparks (Reno) is probably a great place to manufacture them entirely.
Tesla has announced their Pickup Truck.
Same conclusion.
All from Sparks.
I was in Line (too) early morning for my Model 3 Reservation on March 31, 2016.
Still Eagerly waiting on my Invitation.
Have seen several, and have had a chance to sit in one and explore some of its nooks and crannies.
Driving one (or my own) is next on the list...
When you are a Tesla Owner (or can go as an Owner's guest), schedule a trip, go, visit and tour Fremont. You will learn a lot.
You probably will not have access to get inside the Gigafactory.
At least for a while.
Maybe someday.
It is still too much of an active Construction Zone.
If you know someone, you might have the opportunity to tour SpaceX.
Same with Boring Company.
Best Wishes!