The comparison is due to all three being the evolutions of the early route birds. That along with the fact that Talonflame evolves from a normal/flying and evidences pointing to Talonflame's focus being on physical attacks and speed, same two key stats of Pidgeot and Staraptor.
First of all, we aren't really sure yet whether Fletchling and its line is going to be an early route pokemon or not.
I remember during the release of the 5th gen pokemon, they revealed Rufflet & Braviary before they revealed the Unfezant line. So, obviously people though that those 2 where going to be early captures, but that wasn't the case in the games.
Next is the ''evidences pointing to Talonflame's focus being on physical attacks and speed''. While it is ok to compare this aspect with Staraptor, i don't think you should put Pidgeot in the comparison listing, because the Pidgeot line is the 2nd weakest of the early birds when you consider both Attack & Speed stats with the others ones. Here is the listing of there base stat (Atk/Spd),
- Pidgeot (80/91)
- Fearow (90/100)
- Noctowl (50/70)
- Swellow (85/125)
- Staraptor (120/100)
- Unfezant (105/93)
As you see, Pidgeot is the 2nd lowest in terms of Attack and Speed. But it is the 2nd one to have a high amount of Special Atk (at 70, beaten by Noctowl with 76).
Also as i have said before, its typing is one of the reasons why we can't compare Talonflame with the other Normal/Flying types. Would you compare Crobat line or Ninjask with other strong Normal/Flying types. They are both among the fastest pokemons in the game (while being Flying types themselves) and are powerful physical attackers as well (having the same base ATK as Fearow) and can be obtained quite early in the games (mostly before the 1st gym battle).
I don't think so, mainly because of there typing. Thats because typing of a pokemon is also important during battles and one can't ignore it while comparing it with other pokemons of the similar category.