I doubt MS is worth $1bn.
He only earned $30m in his last year with Ferrari as a retainer. Although with personal sponsorship that could have taken him up to around the $80m mark. He didn't earn that when he started, and he wasn't on that with Ferrari until at least the 2002 season.
Then you need to factor in the 20% Willi Weber got from that.
A realistic estimate would put him in the $200-$400m bracket.
Its a bit like the Paul McCartney, heather issue when she said every knows he is worth £800m and it turns out he was worth about Half that.
If Lewis does as well as MS and is on the sport as long, he could be the first F1 Driver $billionaire, but he is going to have to work at it.
Where do they get the $140m for a 5 year contract from? $28m a year? Hmmm.
And with it comes included, TAG H, Mobil, Vodaphone and Mercedes requirements. Not to mention Johnny Walker, Tag aviation etc.