AAA games these days do come out with 64bit executables. For example Fallout 4 is 64bit.
The most important question one should be asking is this: Does the game needs to be 64bit ?
The important difference of a 64bit game is that it can use more RAM than a 32 bit game. There is also the additional benefit that 64 bit variables (for example decimal type) are processed faster because they are not cut in half, but this kind of variable rarely is used in video games, it's mostly used for money calculation in bank software etc.
So if a game doesn't really need a 64bit executable, why should it have one ? Remember that 64bit software can't run on 32bit operating system. So there is no need to make a game available for less people if the game doesn't really need the more RAM.
As for the "bit wars" of consoles of the past, it was all a marketing trick, and the number of bits was referring to different things in different consoles.
For the NES, SNES, and Sega Genesis the 'bits' (8, 16, 16) were referring to the color depth capability of the GPU. Playstation 1's 32 bits were referring to the actual processor, and N64's 64 bits were referring to the bus bandwidth of the GPU.
The processors and the games of consoles have been running on 32bits from the console generation of PS1 and N64 up to the generation of XBOX360 and PS3. Only in the latest generation of XBOX1 and PS4 the CPUs and games of consoles made the jump to 64bit computing.