“The Rav Shach story is missing information, there are people who are willing to do any averiah to get an account or job , we are not talking about that”
I’m not sure what information you think the story was missing.I think you may have missed the point of the story. The point was that Rav Shach said the parnassah comes from Hashem, and no one else can take away your parnassah, and you can’t get something that you weren’t meant to get.
If you do the right thing, you don’t lose out, period. That was the point. If the halacha is that you are not allowed to shake hands, then you don’t have to worry that you will lose out by doing so.