Just a thought I had that we might like to discuss.
Obviously the graphics would be less detailed, but what other outcomes could there be?
What would it all look like? Would the game still be as good? Would the franchise still be as successful and famous? Would there be some nostalgia value to it? Would it even be exclusive to PS1? Would it be owned by Sony or Universal? Have any other hypotheses?
It might not be as popular as it currently is, but it could be? If Insomniac created Ratchet instead of Spyro (all or just 3, i don't know, it doesn't matter) Universal would own it. And Insomniac couldn't continue to use it for PS2 or PS3 if they make the decision to leave Universal and work straight with Sony.
It's funny, a lot of people I knew who thought they played Ratchet & Clank when they were younger claimed "oh, yea I was quite the pro, I actually owned the original on PS1." it's sad the large number of people that said that, and legitimately believed it. Then i'd get all angry and point out Spyro, and how Ratchet came to be (mentioning the troubles with Girl With a Stick) and end by listing all of the Ratchet games and their releases. Totally blowing my cover as a secret Ratchet & Clank fan 
If Insomniac created Ratchet instead of Spyro (all or just 3, i don't know, it doesn't matter) Universal would own it. And Insomniac couldn't continue to use it for PS2 or PS3 if they make the decision to leave Universal and work straight with Sony.
Ah, but what if they had created Ratchet and Clank after creating and leaving Spyro, and it was on PS1 anyway?
Well they started working on Ratchet in 2000, and finished in 2002. There was however a lot of mucking about with Girl with a Stick, and they came up with the concept for that night-something game. So it took them a while before coming to Ratchet & Clank. But doing the new IP with PS1 tech would have been easier for them, and development would have been shorter I'd imagine, so it would probably have come out earlier in 2002.
The quality of the game would be really poor, and most would (I imagine) have moved on to the awesome PS2 after 2 years of it's release. I don't think Ratchet & Clank would have taken off to a good start at all. And Insomniac would probably have left it behind as they did with Disruptor. To move onto the PS2 with another IP. Or, they could work on Going Commando (or the equivalent) as they see potential, or have plans for the sequel.
If I were Insomniac I would have made a sequel on the PS2 for sure, as I know where the series can potentially go.
I'm not sure,personally i don't think the series would be as popular if it had been on PS1,the first game was one of the first on the PS2 and came out with a bang,amazing graphics,huge explosions etc.
Ratchet and Clank was actually a few years late to the PS2.
It could have been huge on PS1, but we will never know for sure.
Oh,never knew it was late,sorry about that 
It was only a couple of years late. one things for sure is that Jak and Daxter was out before Ratchet & Clank.
The reason Ratchet & Clank was out kind of late (2002) is because Insomniac didn't want to let Spyro go that easily. So they shoved another Spyro game out while Naughty Dog was doing their PS2 game.
Before I was a fan I actually asumed there were PSX games too. I think it has been a good choice. R&C belongs on PS2. A brand new start for Insominac on a brand new console.
