1. Most roofs aren't flat.
2. For pitched roofs, you're only going to want to install on the south or west facing sides. So only some percentage of your roof area is ideal.
The WARN Act is not severance! It requires that the company notify employees 60 days in advance of a mass layoff. They don't have to specifically notify the individuals being laid off.
There is no requirement for severance in California!
If she is not your spouse, then she will not be able to accompany you on your TN visa. If she is your spouse, she can enter on a TD visa while accompanying you. The TD visa does not have work authorization so she will not be able to get a work permit. So to answer your question: Never.
However, being in the US will allow her more opportunities to interview with companies that may be willing to sponsor her on other visas that will grant work authorization.
CPT is a great option because it is a quick approval process only involving your school's advisors (only weeks vs months for an application to USCIS/DHS). The downside is that you need to be able to enrol in an internship course that is necessary for your degree, and pay the tuition.
I think you meant "disincentivize". I agree that there should be strong incentives to spread prosperity to smaller towns. Japan has an interesting tax program that boosts the small towns in the country: https://www.kalzumeus.com/2018/10/19/japanese-hometown-tax/
I recently spent a weekend in a major city without Uber/Lyft. Trying to call a cab company was terrible, relative to the user experience of Uber or Lyft.
After making my request, a few cab companies simply answered "Ok" before hanging up. I called them back to get an ETA, and their dispatchers would give me answers like "30 to 40 minutes" or "I don't know".
I wasn't out in the boonies or anything. I was downtown.