nprofile1qy2hwumn8ghj7un9d3shjtnddaehgu3wwp6kyqpqr9ymghn3qk4f6dzcnz4e3zxzptvacqmz6yghmzcz9ndwv6rgep2qcmt9cc (nprofile…t9cc)
I think the big reason is as nprofile1qy2hwumn8ghj7un9d3shjtnddaehgu3wwp6kyqpqwkl48azv70nxj7ef7rjlpmmvpfa5h5k4l24sqjt6940js7hlapxq2wn7a3 (nprofile…n7a3) mentioned: The PS1 used the 4 button front and was hugely successful, and Sony hasn't significantly changed the design.
If you have Nebula, LowSpecGamer has a nice video about the history of the PS1 controller. But the gist is: the lead on the Playstation kind of just wanted the SNES controller, maybe because of the prior work with the Nintendo Playstation. The controller designer had to pull some fast ones to make it different at all.