Tomic's dad was a bus/taxi driver and mom is a biomedical scientist but worked as a nurse. I doubt they were very rich.
Before Gulbis it was Martin Verkerk the richest guy on tour, and just like Gulbis, never had to try because of his dad who had some trash sorting company or something similar. Verkerk admitted in the interviews he just traveled the world for pleasure and not to play tennis, he was permanently drunk or high because he never had to care about anything. At one day he told himself he couldn't live like this anymore and... fluked that RG final! And then was celebrating the success for so long until he fell into obscurity again.
I wonder if Gulbis can ever be such a one slam wonder
I actually find it funny you will find these rich chaps playing futures, maybe sometimes even challengers, but they don't break through. Instead you will get stories like Davydenko's, who had to eat potatoes every day to save up after he emigrated to Germany, or El Aynaoui's, who had to clean the gym at Bolletieri's to afford practising there. Or Dustin Brown's who was a model to collect funds fo tennis trips.
Maybe these things make you stronger, when this is your only hope you cling to and you don't have a safe landing guaranteed, if to compare people with the same amount of talent.