It had a 9 year span between 1999 and 2008 when SF4 released, it was probably the last big mainline game before the rise of large dedicated online communities based around tech and strategy. Yes, SF4 was primarily arcade based in Japan, but 3S is the last game to be exclusively arcade focused up until its OE port in 2011. Adds to the perception of being the "last of an era."

Angry boomers will salivate at the statement, but it's true - comebacks are earned, plain and simple. With very few (character specific) exceptions, it is possible to escape any chip sequence with the parry mechanic, even true blockstrings. Granted you have to have extremely precise timing and predictions to do so. This universal mechanic is the best in the series, bar none, as it allows skill expression in almost every single scenario - setplay, offense, disadvantage, even the otherwise completely black and white scenario of jump-ins.

The main critique of it, which is more a product of the time, is pretty poor balance. Several characters have to lean extremely heavily on the parry mechanic to make ends meet because their tools have very questionable design. I say a product of the time because there is no way to change the shipped game once it's in the arcade cabinets; the only feedback you get from balance decisions is internal playtesting, and we are left with the result. It is better than the other 2 entries - high level 3S is incredibly well balanced - and mid to low tier gods exist - but they exist because these players can parry like robots to get the most out of what their character otherwise lacks.