I believe that if GT5 was developed for PC, it would have released a lot faster. This I believe was due to a lot of time was spent on making all the new effects such as rain, day and night cycles, tyre smoke, skidmarks run all at 60fps at 1080p on the PS3. You also have to remember the limited amount of memory the PS3 has 512MB total ram, including system and GPU memory. At the end of the day, top smartphones out now have as much memory if not more, and by 2011 that will be almost standard. Memory is however only useful for high resolutions, the actual GPU in the PSU is slightly worse / equivalent to what you will find in a mid-range laptop costing about £400-£600 in UK shops. If they released GT5 for PC as it is now (Apart from moving the weather effects and tyre smoke from Cell processing to GPU Processing) then most low to mid-range gaming PCs made in the last year should run GT5 much better with no jaggies and at native 1080p. This can be also said for most mid-range gaming laptops bought this year should run GT5 better than the PS3. Polyphony Digital are very good at optimising games so they could easily have added very low settings that even low end gaming PCs could have run the game at high frame rates. I don't get why people expect GT5 to look way better than current 30fps racing games that run at 720p, it is not fair as they can do more effects and have higher graphics detail. Also people in doubt about laptops being able to run GT5 well, then why can laptops play games that struggle to run on the PS3 at 30fps at 720p, GT5 runs at 60fps and 1080p so should be a lot easier to run provided they switch some of the Cell effects to the GPU side.
People think that you have to spend a lot to have a gaming PC but that is not the case. All you have to do is spend smartly, so best thing to do is buy mid-range parts, keep a cheap GPU spare, and keep upgrading every 6-12 months by selling the older parts. You will lose very little money about £30 on each upgrade but your machine keeps updated and becomes more power efficient. If you spent about £300 on a gaming PC now, you should be able to play most multi-platform games on high at full 1920x1080 at 60fps including games like F1 2010.
I am annoyed with Sony sticking with there original RSX GPU based on the 7800 GTX. The fact they released the PS3 about one year later than the Xbox 360 with a less advanced GPU annoyed me. They are similar in terms of graphics processing power. The reason why PS3 exclusive games look good is due to a lot of extra effects are done on the Cell processor but multi-platform games generally look better on 360 due to the more advanced GPU in the 360 (It's easier to make games for due to Unified shader.) They should have delayed the PS3 by about 3 months and included a GPU based of the 8800GTX (DirectX 10 effects too). That was one immense card for gaming PCs and is probably twice as fast than the one in the PS3. If they used that as the base GPU then, the PS3 would of eclipsed the 360 very quickly as every multi-platform game, would of looked way better, and GT5 wouldn't have those fuzzy shawdows and maybe would have been released earlier.
Polyphony Digital used the things they learnt when producing GT on the PSP to make GT5 better as both the systems have very limited memory. The effort taken of making the game have basic effects such as the shadows, 2d trees and crowds to keep at 60fps would not have been needed as if the RSX created from the 8800gtx would most likely have had more memory but at least 50% more GPU power (even if it's a stripped down 8800gtx). The game would not only have had had better effects such as 3d trees but no jaggies as well. If they used the delay caused by the blu-ray standards and production to improve also the GPU of the PS3, then we could have seen a different story for the PS3. In hindsight it is probably easier to say but I'm sure Sony had good contacts with Nvidia to know there newer GPUs launching would have been much better to include. I could understand if they did not inlucde the newer GPUs if they were only about 20% faster but 80%+ is a big reason to change your minds. I'm sure the developers wouldn't have minded to have a system with a lot more memory and GPU power. It would have given the PS3 the upper hand by a big margin over the 360.
Anyway for people who say you have to spend £1000 to be able to game just a bit better than the PS3, I will let you know that if you spend that amount today, you will most likely have at least 20 times the graphics processing power of the PS3. Imagie what Polyphony Digital could do with 20 times the GPU of the PS3.
I am personally hoping the PS4 launches about 2013/2014 as by then CPU and GPU technology would have become very hard to shrink much further. Also it will allow for slims of the PS4. It should also be about 30 times more faster than the PS3 if they use mid-range parts available then. This will finally allow Polyphony Digital to recreate photorealistic graphics (Yes that also includes 3D trees). I think Kaz's vision won't be met until PS5 though as he wants to use ray tracing. Maybe possible on PS4 but this will limit the number of cars on track and he may even think about including 2d trees to compensate the game to run at 60fps (Joking). I think he's changed his mind about GT6 for PS3 and may have got the word from Sony about a PS4 launching in about 2-3 years time, and to make it a launch title. So he may use GT5 as a big beta to see what people like and experiment with new updates. So when GT6 hits the PS4 people will be amazed. I think the car count will also reduce by 50%. (This is pure speculation but this is the feeling I'm getting from Kaz's mindset from his tweets and interviews. The only thing I can think that would be different is, he releases GT6 at the end of the PS3s life as the top Sony console and releases GT6 also for PS4 with much better graphics or just calls it GT7.
Most of graphics bugs and effects are due to a limitation of the PS3 and not Polyphony Digitals fault. They are running at the limit of what the PS3 has to offer like us guys / girls trying to get a gold in the hard challenges but now thinking of ways to shave the last few tenths to get the shadows looking better. Also for the people who complain about GT5 not having 3D trees, that is due to PS3 limitations, don't blame Polyphony Digital as they would have included it if they could provided it ran at 60fps.