When PGR4 came out I remember reading at the time the development team felt that they would only make another game, (after 3), if it offered something different to the previous games. They asked the community and PGR4 was released with weather, lots of weather
and motorbikes.
Yes it's a massive shame they got closed as if you think about it at the time they were Microsoft's leading car game developer, by the time FM1 released Bizzaire had already released 3 games in the MSR/PGR series.
They really were ahead of the game, PGR4 was released with a few bugs that due to the Activision acquisition never got fixed, eg cannot run the game off the hard drive without the sound bug, no HUD in cockpit view, but based on how good the series was, imagine how great PGR5 would have been and I wonder where we would be now ?
I often think why didn't Microsoft purchase them ? Seemed like a no brainer at the time.
I also wonder why Martyn Chudley sold his company in the first place, I have never been able to find any details about this.
Edit, just found out, he wanted to spend time with his kids who were young at the time, fair enough.