It stopped mattering, and was mainly a marketing tactic anyway.
Wikipedia -
Bits
Each new generation of console hardware made use of the rapid development of processing technology. Newer machines could output a greater range of colors, more sprites, and introduced graphical technologies such as scaling, and vector graphics. One way console makers marketed these advances to consumers was through the measurement of "bits". The TurboGrafx-16, Sega Genesis, and SNES were among the first consoles to advertise the fact that they contained 16-bit processors. This fourth generation of console hardware was often referred to as the 16-bit era, and the previous generation as the 8-bit.
The bit-value of a console referred to the word length of a console's processor (although the value was sometimes misused, for example the TurboGrafx 16 had only an 8-bit CPU, and the Genesis/Mega Drive had the 16/32-bit Motorola 68000, but both had a 16-bit dedicated graphics processor). As the graphical performance of console hardware is dependent on many factors, using bits was a crude way to gauge a console's overall ability. For example the NES, Commodore 64, Apple II, and Atari 2600 all used a very similar 8-bit CPU. The difference in their processing power is due to other causes. For example the Commodore 64 contains 64 kilobytes of RAM and the Atari has much less at 128 bytes of RAM.
The jump from 8-bit machines to 16-bit machines to 32-bit machines made a noticeable difference in performance, so consoles from certain generations are frequently referred to as 8-bit or 16-bit consoles. However, the "bits" in a console are no longer a major factor in their performance. The Nintendo 64, for example has been outpaced by several 32-bit machines.[52]
