In that case they'd on average have 100B each, doesn't sound like "new billionaires" to me. Either way, I'm sure these 142 people work harder/have more influence combined than all but two entire countries in this world. /s
Wealth and GDP are measuring different things, even though both are measured in dollars. It's a bit of a weird comparison for that reason, but still shows ridiculous levels of inequality.
Wealth is how much money you have right now. GDP is how much value the country generates in a given year.
So wealth is kinda like how much you have in the bank, while GDP is closer to how much money is changing hands in a country over a given year. There's a common joke about GDP - if two people paid each other $100 to eat a pile of shit, GDP went up $200 even though no real value was generated. In this example, neither of their wealth changed.