Competitively, this is probably true. They both have the same number in OU and UU: two and three. And while Crobat is BL, Weezing, Drapion, and Toxicroak see nowhere near the usage of Blaziken, Typhlosion, Arcanine, and Moltres. But note: except for Arcanine, every relevant Fire-type is either a starter or a legendary, all the way down to NU, where the best Fire-type is still Charizard!
See, I was talking about single player, where there are only two types of games: those with Growlithe available early and those with no relevant non-starter Fire-types until the legendaries like Ho-oh and Heatran show up. Meanwhile, players can pick up Poison-types as early as the first forest and continue getting strong, relevant ones with mainstays like Tentacool and Zubat as well as newer contributors like Roselia. With Fire, you can take Chimchar, settle for the woefully-underpowered Rapidash, or just settle for playing the entire main storyline with no Fire-type. There is no reason at all for this.
That's true-- and Growlith always appear very late in the game, and doesn't even get flamethrower until level 35!! Plus you need fire stone to evolve it, not easy. Needless to say, it's not an ideal in-game fire type.
In HGSS there's houndour too, but houndour doesn't get flamethrower until level 43 (48 for houndoom) and doesn't evolve until level 24. Neither pokemon appears before the 3rd gym (and then is severly under-leveled) . . .
Despite this lack of fire types in game though, there's one thing I have to point out-- in terms of coverage, there's really nothing a fire type does that can't be accomplished by a water type, often times better. Except for Grass (which is shitty and is weak to ice), there's no type that fire hits that Water can't hit for at least neutral. Taking STAB boost into account, as a primary attacking type, Water completely outclasses Fire, and this effect is felt even stronger in-game.
Even on the defensive side, Water shares Fire's 3 best resistances, fire, ice and steel, and has better weaknesses (I'll take being weak to electric/grass any day over being weak to water, rock and ground).
In other words, while pokemon like Salamence and appreciate fire attacks for super effective coverage (as well as anything that truly hates scizor/forry), in terms of choosing a type to actually
be . . .
Almost every fire pokemon would have been better off if it had been born a water type instead, in-game or competitively.
Seriously, take any fire type, imagine it as a water type with the same movepool (save all the fire moves water moves instead with ice moves added to its pool), and you'll see that it would be a much stronger pokemon.
Infernape? Heatran? They would be so much tougher and destructive if they had SR resistance, water type and STAB Hydro Pump instead.
Pretty much the only perk to being a fire type (over water) is Overheat, because if water had an overheat-esque attack on pokemon with decent sweeping stats, it would have a similar effect on the game as Draco Meteor due to Water's insane neutral coverage. Oh, and being immune to burn is nice, but I'd still rather be non-SR weak, especially since both types are primarily special-attacking.
. . . so, in short, if you're hard up for a fire type in-game, you could always pick up a tentacool?