How's that? On paper the pet looks pretty decent. At level 11 where the Hunter gets Volley, the Beastmaster gets one attack of his own and two attacks at +10 (1d4+8 piercing + 3d6 poison, save for half) from his AC 18, 40 HP pet cobra (with blindsight). Depending on party composition that cobra could have up to 15 temp HP for an effective 56 HP. It's nowhere near as durable as an earth elemental, and it's nothing to get really excited about given that the ranger can summon eight cobras with a single spell, each of which is about half as good as his pet cobra... but I wouldn't say that it's not contributing in combat. The ranger's overall DPR is comparable to a Sharpshooter fighter's DPR of the same level, e.g. about 34 DPR (with Sharpshooter) against an AC 18 Drow Elite Warrior, whereas a GWM fighter of the same level would be doing 24.15 DPR, or 32.20 on rounds where he gets a bonus attack.
I still think Hunter is preferable, and the Beastmaster's action economy in RAW grates on the imagination... but mechanically it's not too shabby even by RAW if you find the right beast. I certainly wouldn't say the beast is useless in combat.