Many military forces take close to zero time pilots and through intense training have them flying supersonic jets on the wing through aerobatics in less than a year. Add another year and they can be flying a front line fighter; add another year or two and they will actually be capable in effectively employing the front line fighter.
So it can be done.
But there is little to parallel this in the civil sector, and even less when it comes to advanced aircraft handling.
AND at the end of that year the newly minted pilots, while good in stick and rudder skills, neither have the experience to know what is good and bad nor do they entirely know WHY the aircraft is behaving as it does through the various flight regimes (or have explored them in very great detail). Or are able to 'consolidate' this knowledge into a larger picture for several years.
AND through this 'consolidation' period there continues to be much activity in actual handling and flying rather than managing automatics or watching air go by (or debating esoterics of rules or minutia).
Even with this, there's a significant spike in accident rates around the 3-5 year point as they become familiar enough to become confident, yet don't entirely have their judgment wrapped around what is going on around them, how things can snowball quickly from good to bad, and how it's better to preempt the bad situations from occurring in the first place.
It don't come cheap--several million dollars invested in a person to have them competent in a major weapons system. In the early to mid 90s, a capable flight lead in a MWS was a "six million dollar man."
Cheap and aviation are two words which cannot live together. You simply must invest in the operators in initial and recurrent training if you expect them to be good and stay that way--and even get better with experience. And there's also simply no substitute for experience.