The thing is that what is Playstation changed over the years. Most of the core gaming market today started gaming on the 7th generation and PS3 in particular took off after Uncharted 2. So they have this idea of PS always being overly reliant on first party when it wasn't always the case.
In the 5th and 6th generation, many of the games that today could be labeled as third party exclusives were the bread and butter of PS. But those were not obtained cutting deals most of the time, PS was simply the platform where developers were comfortable, the de facto standard. Sega was dying. PC was an entirely different thing, and unknown for japanese devs and Nintendo dropped the ball 2 generations in a row. Specially regarding storage that did not meet the needs of many developers. First cartridges and then those odd mini DVDs.
Xbox got late to the party but slowly started building third party support with the first console. Was surprised at the time seeing games like Project Zero on it, which ran amazing on the console.
In the 5th and 6th generation, many of the games that today could be labeled as third party exclusives were the bread and butter of PS. But those were not obtained cutting deals most of the time, PS was simply the platform where developers were comfortable, the de facto standard. Sega was dying. PC was an entirely different thing, and unknown for japanese devs and Nintendo dropped the ball 2 generations in a row. Specially regarding storage that did not meet the needs of many developers. First cartridges and then those odd mini DVDs.
Xbox got late to the party but slowly started building third party support with the first console. Was surprised at the time seeing games like Project Zero on it, which ran amazing on the console.