I'll have to make some quick conditions for this post.
- The Extreme E cars were technically 1 model with 9 separate liveries, so, the other 9 models are recycled IMO
- The Viper AE is technically a recycled SRT Viper GTS model with new parts exclusive for it
Looking back at the end of the car pass (5 updates after the car pass ended):
FH4 (Series 9-14):
New-To-Forza Cars: 22
Recycled Cars: 10
360-Era Returnees: 3
FH5 (Series 10-16):
New-To-Forza Cars: 11 (as of Series 16; 21 if the conditions are ignored)
Recycled Cars: 35 (as of Series 16; 25 if the conditions are ignored)
360-era Returnees: 0
The last 360-Era returnee was the Plymouth Barracuda Formula S in Series 9.
Comparing this to FH4, I can't imagine what the future of Forza Horizon 5 will have, with all these recycled cars. I mean, their work for the Fable reboot is considered and the work done for the 2nd expansion, that's understandable but, in reality, FH5's recent content updates have been filled with more recycled content than never-before-seen cars in the franchise. I do not know what to say about this. But hopefully, after the 2nd expansion comes out, Playground would have the guts to bring more New-to-Forza cars/360-era returnees/Exclusive Forza Motorsport DLC (Aztek, Caparo T1, 904, 924 GTS, Safari Turbo, Odyssey, 2017 Continental) into the playlist over recycled FH4 models in future updates.