Nintendo's policies to third parties were draconian in the 80s/90s, that said Playstation fans always convienantly gloss over the Genesis. The Genesis provided competetion, so by the early 90s, Nintendo's "monopoly" on the console market was a non-issue.
Also the whole "consoles were toys before" is such a lark too. The Sega Genesis and Sega CD were designed to look like high end stereo components for an adult, not toys, so again, Sega did that first.
If anything Sony did nothing but rip Sega off ... Crash Bandicoot is an obvious knock off of Sonic the Hedgehog, Tekken was their answer to Virtua Fighter, Ridge Racer to Sega's arcade racers. Sega was already doing all the same stuff in the mid-90s, Sony just piggy-backed on what Sega was doing and took advantage of poor decision making by Sega's Japan division.
If there was no Playstation, the Saturn simply would've just taken the third party titles that Sony got (FFVII, Tekken, MGS, etc.) and they would've sold 80-100 million Saturns, thus putting them in a great position for the following gen. Nintendo would've taken their licks and come back at Sega the next-gen with the GameCube.
