False premise. No two people, even close relatives, will ever have completely identical interests nor will the ever share identical experiences.
“false premise”
You can’t have false premises in a supposition. It’s a hypothetical, a ceteris paribus exploration of whether Bill Gates would have been a failure if someone else had gotten some of his “luck.”
Yep.
Even so, this is a classic straw man argument, also it assumes that if the "pretend brother" invented Microsoft, then Bill would be a "Disaffected Blue-Collar Grunt", or somesuch.
Why couldn't BOTH brothers be successful? One reinvent software, and one reinvent hardware? Or both of them team up to quadruple MS in size? Or some other premise?