The SNES was introduced with a "slower processor", and this was used as a marketing ploy by SEGA. However, this was not a real issue with the SNES, as it was considerably a much more powerful console capable of better graphics, and audio...even without the use a CD add-on.
As the SNES aged, and the 32 bit era began to roll in, Nintendo was ready. The SNES was "future proofed" to an extent. This allowed Nintendo to ensure they could market the console without having to jump to a new unit hastily. The biggest method for future proofing was the ability to add on special "chips" into the cartridges that allowed games to be "bigger" than traditional SNES 16bit games. A prime example is the Super FX chipset that allowed the SNES to present 3D rendered polygons. One memorable game that used the Super FX chip was Star Fox.
The Super FX wasn't the only chip though. There were a handful out there, and this wasn't exactly a bad thing. Some companies needed specialized chips to accomplish goals in their games. There were games that displayed 3D rendered graphics without special chips, such as Star Trek Starfleet Academy, with varying levels of achievement. (For a list of enhancement chips, click here -https://goo.gl/4HRBjl)
The SNES has spawned it's share of classic franchises along with mainstays from the NES days. Such as Donkey Kong Country, Star Fox, Super Mario Cart, and others.
The SNES was finally discontinued in North America in 1999. In Japan, the SNES lasted until September 25, 2003 alongside the NES.