Forza Motorsport 3 DLCs

Why is it not possible to redeem codes or buy Forza Motorsport 3 DLCs?

Thanks!

They have been End of Lifed and it is assumed that licensing is the issue.

With cars I get but the made up tracks of Benchmark and Sidewinder given away free at the time but inaccessible now. Short sighted thinking by T10/Microsoft. Its like they don’t want me to play FM5, FM6 or FM7 as looking at comments no support, glitchy leaderboards (ruined by cheaters - would have thought they’d fixed that). Oh well.