From what I've seen, getting a regular job in classical music is difficulty and pressure on a level few of us can imagine. Might be easier to get tenure at Harvard than a rostered spot in an orchestra.
I think the odds of getting a high-profile orchestra slot are far lower than that.
Source: Multiple orchestra musicians and management speaking about the audition process and the now-defunct myauditions.com website
Process:
Show early talent
Get the right instruction
Get into a preparatory program
Make it into a conservatory
Do well once there
Get a spot in an ensemble, probably lesser-known (not easy) and establish a reputation
See an audition notice with repertoire to prepare, apply
Spend a few weeks or months intensively practicing (on top of other commitments)
Maybe get an audition, realizing the Music Director may be promoting his buddy past these rounds
Travel at your own expense to the audition
Play demanding repertoire behind a screen and respond to any directions
Most likely get rejected
Play in any following rounds
If not rejected, maybe you get a qualifying week rehearsing with your potential colleagues and playing a couple of concerts when the Music Director is in town
If you beat out the couple of stellar artists who've also gotten that far, you may get an offer
Or, the MD's buddy may get the offer
Or, there may be a no-hire
If you get and accept the offer, you are "on approval" for a couple of years at which point there's the Tenure Decision
