I don't even have a PPL yet, but what I can tell you is that bizjet is an industry very particular.
As FO you can have 10000 hours, all of them as PIC and on IFR flight on jet aircraft like the A380 or a Global Express, but if you know nobody you have no chance to get in. You need to know somebody in the company, or somebody that knows somebody in the company.
As you said, more hours are required than airlines usually do, thus airlines might even become a mile stone to get a seat in a bizjet.
They key word is network, network and, again, NETWORK!