Why don't they just start a company in the country where they are from or why don't you start a company with someone who is a citizen or has a green card?

The entire premise of your question is misaligned with the intention of the H1-B visa. Yes, everyone abuses its intent, but that isn't justification for more people to find more ways to abuse it. The abuse of that visa (and other visas) is why folks just want it abolished outright. I guess the purpose of a system is what it does, but it was sold to the American electorate as a way for companies to get access to talent that they simply cannot find domestically.

Trying to use the H1-B to hire a very specific person instead of any person with the skillset needed for the role would be in contradiction with the labor market test (LMT) needed for PERM status.

An H1-B can only work for the employer on the I-129 petition. There are some forms of passive income allowed but to placing shares in a trust and having an unpaid board seat just seems like an attempt to cheat the process because ultimately the goal is for her to work for this startup. Doing what your proposing puts a target on her head where anyone that is anti-H-1B can report her to USCIS and get her deported.

Moving home, working remotely and then applying for an L-1 seems like the correct approach here for what you're trying to do.