We say that there is a reason anesthesia residency is 3 years.
To be good at intubating, you only need 2.
On the serious side, it doesn't matter only how many you do, but also the difficulty of the airway and the quality of the teacher. The latter is usually deficient in both ICU and ED, so one can have 200 intubations and still f up. We see it on a weekly basis.
Typical example (true story): 50 year-old patient with severe allergy to ACEI, swollen lips and airways, some SOB, but still conscious, breathing and satting 98%. Anesthesia team asks for ENT at bedside. ENT comes and asks for a cric kit and for the neck to be prepped, just in case.
While people are still looking for a cric kit, the ED attending induces the patient on her own, without letting anybody know (at that point, there are 3 anesthesia and 2 ENT people at the bedside, waiting for the cric, patient still doing OK). Difficult glidescope intubation ensues and, thank God, succeeds. But the IQ and stupidity of the ED doc, OMG! I doubt the ED residents present learned a lot there, except how to be stupid macho.