And I can assure you not. 8 months on main + 4 months on alt. So effectively 12 months. Headbutting daily for a Fletchling. I have got 2 h.a. Fletchlings in that time. One of them is Calm (had good IVs too, such a waste), the other one is Hardy with average IVs.
Besides Fletchling, which is limited, I really can't be sure about getting a +29 IV extremely rare. Especially with a hidden ability. I don't have a single one. Got a few 20+ non h.a. ones though.
Not trying to argue, just pointing out. I don't mind any of the staff using stuff like 30+ IV hp fire Serperior, h.a. Talonflame, h.a. Amoonguss or whatever. I don't have any problems as long as they're obtainable in some way for normal players.
Thank your choosing the probably most rarest thing in the game, I played around 2,4k~ hours with maybe headbutting once a week and got 1x good and 1 epic fletchling in that time. It certainly is possible and even if you don't agree, +20ivs on the staff pokemon would make a damage difference of about 2-4%
You are not taking in count the best stat: speed, which they always set to 31...